Serving as one of the fundamental structural components of the biological world, alanine bridges protein architecture with complex intermediary metabolism. As an aliphatic, non-essential amino acid, it not only stabilizes helical folds across proteomic landscapes but also operates as the primary currency for nitrogen clearance and gluconeogenesis between peripheral muscle beds and hepatic parenchyma. By coordinating systemic metabolic homeostasis under diverse physiological demands, alanine exemplifies how a seemingly simple molecular structure drives profound biochemical operations.
Alanine
1. Concise Definition
Alanine (systematic IUPAC name: 2-aminopropanoic acid; abbreviated as Ala or A) is a non-essential, aliphatic, proteinogenic alpha-amino acid characterized by a nonpolar methyl (-CH3) side chain. Within biological systems, its chiral L-isomer represents one of the twenty standard building blocks directly encoded by the universal genetic code for ribosomal protein synthesis. In physiological solution, alanine functions as a zwitterion and occupies a pivotal position in carbon and nitrogen exchange across tissue types.
Beyond its structural role in macromolecular assembly, alanine serves as a vital biochemical intermediary connecting glycolysis with the citric acid cycle through reversible transamination reactions. Its carbon backbone is inherently gluconeogenic, meaning that deamination produces pyruvate, which directly fuels de novo glucose production during nutritional deprivation or prolonged physical exertion. Consequently, alanine acts as both a cellular scaffold and an essential substrate within systemic bioenergetics.
Furthermore, alanine exhibits distinct biological roles depending on its stereochemical and structural configuration. While L-alanine dominates eucaryotic cellular biology and translation, its enantiomer D-alanine is an essential component of bacterial peptidoglycan cell walls, and its structural isomer beta-alanine serves as the rate-limiting substrate for intra-muscular dipeptide synthesis. This structural versatility establishes alanine as an indispensable subject across biochemistry, physiology, and evolutionary biology.
2. Etymology & Linguistic Origin
The term alanine was coined in 1850 by the German chemist Adolph Strecker. Strecker synthesized the amino acid in a laboratory setting prior to its widespread biochemical isolation from natural proteins, deriving the compound via the reaction of acetaldehyde, hydrogen cyanide, and ammonia—a chemical sequence now canonically recognized as the Strecker amino acid synthesis. To denote its chemical provenance from aldehyde precursors, Strecker derived the root Alan- from the German term Aldehyd, appending the chemical suffix -in (standardized in English as -ine), which designates neutral or basic nitrogenous organic compounds.
Linguistically, the root aldehyde itself was originally formulated as an abbreviated compound term by Justus von Liebig from the Latin phrase alcohol dehydrogenatus, meaning “dehydrogenated alcohol.” Thus, the etymology of alanine preserves a direct historical reference to nineteenth-century synthetic organic chemistry. The nomenclature was formally integrated into chemical lexicons worldwide, maintaining uniform etymological lineage across Romance, Germanic, and Slavic scientific vernaculars.
3. Pronunciation & Grammatical Form
In standard international scientific English, alanine is pronounced phonetically as /ˈæləniːn/ (AL-uh-neen). Grammatically, the term functions as an uncountable common noun when referring to the chemical substance as a bulk compound or biological substrate, though it may take a countable plural form (alanines) when referring to specific residue positions within a polypeptide chain or structural mutations in molecular biology contexts.
Standard biochemical abbreviations include the three-letter code Ala and the single-letter IUPAC/IUBMB designation A. When distinguishing its isomeric configurations, scientific convention requires prefixation designating stereochemistry or positional isomerism, producing terms such as L-alanine (the physiological proteinogenic enantiomer), D-alanine (the dextrorotatory enantiomer found in microbial peptidoglycans), and beta-alanine (the beta-amino acid structural isomer featuring an amine group attached to the beta-carbon).
4. Detailed Conceptual Explanation
At the molecular level, alanine possesses the chemical formula C3H7NO2 and a molecular mass of approximately 89.09 g/mol. The molecule centers on an alpha-carbon atom bonded to four distinct chemical moieties: a basic amino group (-NH2), an acidic carboxylic acid group (-COOH), a single hydrogen atom (-H), and a nonpolar, hydrophobic methyl side chain (-CH3). Because the alpha-carbon is bonded to four chemically distinct groups, it represents a chiral stereocenter, yielding two non-superimposable mirror-image enantiomers: L-alanine and D-alanine. In aqueous biological environments at physiological pH (approximately 7.4), alanine exists predominantly in its zwitterionic form, wherein the carboxyl group is deprotonated into a negatively charged carboxylate (-COO-) and the amino group is protonated into a positively charged ammonium ion (-NH3+).
From a biophysical standpoint, the methyl side chain of alanine exerts a profound influence on macromolecular architecture. Being chemically inert and lacking reactive heteroatoms, the methyl group neither forms hydrogen bonds nor participates in ionic interactions. However, its small steric footprint and moderate hydrophobicity impart exceptionally high alpha-helical propensity. In polypeptide folding dynamics, alanine residues stabilize alpha-helices with minimal steric clash against the polypeptide backbone. When proteins fold within aqueous solvent environments, alanine residues frequently cluster in transitional hydrophobic cores or align along the interior faces of secondary structural motifs, contributing to structural stability through van der Waals packing and the thermodynamic entropic gains of the hydrophobic effect.
In systemic human physiology, alanine functions as the premier vehicle for non-toxic inter-organ nitrogen transport. During periods of skeletal muscle catabolism, high rates of amino acid deamination generate free ammonium ions (NH4+), which are neurotoxic at elevated concentrations. Instead of liberating free ammonia into circulation, skeletal muscle cells transfer nitrogen to alpha-ketoglutarate, yielding glutamate. Subsequently, the enzyme alanine aminotransferase (ALT) transfers this amino group from glutamate onto pyruvate (a terminal byproduct of glycolysis), forming alanine and regenerating alpha-ketoglutarate. Alanine is then exported into the bloodstream and delivered directly to hepatocytes in the liver.
Upon hepatic uptake, ALT catalyzes the reverse transamination reaction: the amino group of alanine is transferred back onto alpha-ketoglutarate to form glutamate, channeling nitrogen into the urea cycle for ultimate renal clearance. Concurrently, the deaminated carbon skeleton of alanine is regenerated as pyruvate, which immediately enters the gluconeogenic pathway to yield free glucose. This cyclic inter-organ shuttle—termed the glucose-alanine cycle or Cahill cycle—ensures the continuous delivery of glucogenic carbons to the liver while safeguarding circulating blood from ammonia toxicity during periods of metabolic stress or fasting.
5. Historical Development
The historical trajectory of alanine spans more than a century and a half of biochemical discovery, beginning with synthetic chemistry and culminating in modern structural biology:
- 1850: German chemist Adolph Strecker synthesizes alanine in vitro via the nucleophilic addition of hydrogen cyanide and ammonia to acetaldehyde, followed by hydrolysis. This discovery established the Strecker synthesis as one of the foundational methodologies in classical synthetic chemistry.
- 1879: Paul Schützenberger isolates alanine from natural biological sources through the acid hydrolysis of silk fibroin, confirming that Strecker’s synthetic molecule was an authentic constituent of living matter.
- 1888: Chemist Theodor Weyl confirms the high-abundance presence of alanine in fibroin proteins, providing empirical verification that amino acids represent modular structural units in complex animal polymers.
- 1901–1902: Emil Fischer and Franz Hofmeister independently formulate the peptide theory of protein architecture, demonstrating that alanine residues link sequentially via covalent amide bonds (peptide bonds) to form extended polypeptide backbones.
- 1969–1970: Philip Felig and George F. Cahill Jr. systematically characterize the Cahill cycle, elucidating the quantitative dominance of alanine in inter-organ nitrogen and carbon flux between human skeletal muscle and hepatic tissues during post-absorptive and prolonged fasting states.
- 1989: James A. Wells and colleagues formalize the methodology of alanine scanning mutagenesis, using recombinant DNA technology to systematically substitute native residues with alanine to quantify functional energetics in protein-protein and ligand-receptor interactions.
6. Theoretical Foundations
The functional attributes of alanine are grounded in classical thermodynamic and biophysical theories of macromolecular folding. In accordance with the Ramachandran plot—which maps the sterically permissible dihedral angles (phi, phi [φ] and psi [ψ]) of polypeptide backbones—alanine exhibits one of the broadest conformational energy landscapes of any amino acid containing a beta-carbon. Because its methyl side chain possesses minimal steric bulk compared to bulkier branched-chain or aromatic residues, alanine experiences minimal steric hindrance against neighboring carbonyl oxygens and amide hydrogens. Consequently, thermodynamic models consistently demonstrate that inserting an alanine residue into an alpha-helix reduces the conformational free energy penalty of folding, giving alanine the highest alpha-helix propensity among all canonical amino acids.
From an enzymatic and kinetic perspective, alanine transamination conforms strictly to the ping-pong bi-bi kinetic mechanism characteristic of pyridoxal 5′-phosphate (PLP)-dependent aminotransferases. Under this theoretical framework, the enzyme oscillates between two covalent intermediate states: an enzyme-PLP Schiff base complex and an enzyme-pyridoxamine phosphate (PMP) intermediate. Alanine binds to the enzyme-PLP complex, donating its amino group to form PMP while releasing pyruvate. Subsequently, an alpha-ketoglutarate molecule binds the PMP complex, accepts the stored amino group, and dissociates as glutamate, regenerating the enzyme-PLP complex. This mechanism ensures strict microscopic reversibility, allowing alanine concentrations to dynamically reflect the cellular ratio of glycolytic flux to amino acid catabolism.
Finally, allosteric control theory accounts for alanine’s role as a metabolic sensor. In hepatic tissue, alanine acts as an allosteric inhibitor of pyruvate kinase, the terminal enzyme of glycolysis. When intracellular alanine concentrations rise—signaling an abundance of amino acid-derived carbon skeletons and an ongoing need for gluconeogenic activity—pyruvate kinase is allosterically down-regulated. This prevents a futile cycle wherein newly formed pyruvate would be converted back into phosphoenolpyruvate and subsequently re-cleaved by pyruvate kinase, ensuring energy efficiency during gluconeogenesis.
7. Key Components, Types & Dimensions
Alanine exists across multiple structural isomers, stereoisomers, and experimental methodologies, each defined by unique biochemical dimensions:
- L-Alanine (L-2-Aminopropanoic Acid): The standard, genetically encoded stereoisomer incorporated into eucaryotic and bacterial proteins. It represents the central substrate for protein translation and the primary transamination intermediate in vertebrate intermediary metabolism.
- D-Alanine (D-2-Aminopropanoic Acid): The non-proteinogenic enantiomer synthesized enzymatically in bacteria by alanine racemase. It is a critical cross-linking component of the peptidoglycan cell wall, protecting bacterial envelopes from enzymatic degradation by eucaryotic proteases.
- Beta-Alanine (3-Aminopropanoic Acid): A structural isomer in which the amino group is attached to the beta-carbon rather than the alpha-carbon. Beta-alanine does not enter ribosomal protein synthesis; instead, it serves as the physiological rate-limiting precursor for carnosine (beta-alanyl-L-histidine) and anserine synthesis in skeletal muscle and brain tissue.
- Alanine Scanning Mutagenesis: An analytical molecular biology paradigm wherein wild-type residues across a protein sequence are systematically replaced with alanine. Because alanine truncates the side chain to a chemically inert methyl group without disrupting the secondary main-chain backbone, this technique isolates the energetic contributions of specific side chains to folding, catalysis, and binding.
- The Glucose-Alanine Cycle Flux: A systemic physiological dimension describing the quantitative rate at which muscle-derived alanine is transported to the liver, deaminated, and re-synthesized into glucose per unit time, reflecting systemic metabolic state and neuroendocrine tone.
8. Examples & Illustrative Cases
To contextualize alanine in practical biological environments, several empirical scenarios demonstrate its functional behavior across cellular and systemic domains:
Case 1: Prolonged Fasting and Gluconeogenesis: In an individual undergoing a 36-hour clinical fast, glycogen stores in the liver become depleted. Under the influence of rising glucagon and cortisol, skeletal muscle initiates targeted proteolysis of structural contractile elements. Intramuscular branched-chain amino acids undergo transamination, transferring their amino groups to alpha-ketoglutarate and subsequently to pyruvate. Alanine is secreted into circulation at rates disproportionately higher than its stoichiometric abundance in muscle tissue. Upon reaching the liver, alanine undergoes deamination via hepatic ALT; the resulting pyruvate molecules enter gluconeogenesis to generate circulating glucose, stabilizing blood glucose concentrations and supplying essential fuel to erythrocytes and the central nervous system.
Case 2: Probing Receptor-Ligand Interfaces: In a pharmaceutical research laboratory seeking to map the binding epitope of a monoclonal therapeutic antibody against an oncogenic receptor, structural biologists perform alanine scanning mutagenesis. Each residue within the predicted binding interface is individually converted to alanine. When Tyrosine-104 is replaced with alanine, binding affinity drops by a factor of 10,000, while mutating adjacent residues produces negligible changes in binding constant (Kd). This identifies the phenolic hydroxyl and aromatic ring of Tyrosine-104 as an indispensable energetic “hot spot,” guiding the rational design of small-molecule inhibitors.
Case 3: Congenital Lactic Acidosis and Pyruvate Dehydrogenase Deficiency: A pediatric patient presenting with severe developmental delay, hypotonia, and chronic metabolic acidosis undergoes plasma amino acid analysis. The metabolic panel reveals markedly elevated levels of both lactate and alanine. Because a genetic deficiency in the pyruvate dehydrogenase complex (PDHC) prevents the entry of pyruvate into the mitochondria for oxidative decarboxylation, intracellular pyruvate pools accumulate dramatically. Mass-action equilibrium shifts this excess pyruvate into two alternative pathways: reduction to lactate via lactate dehydrogenase, and transamination to alanine via ALT. Elevated plasma alanine thus serves as an important diagnostic signpost for mitochondrial respiratory chain and pyruvate oxidation defects.
9. Measurement & Assessment
The quantification and functional evaluation of alanine span clinical diagnostics, analytical biochemistry, and structural metabolomics, using various sensitive methodologies:
- High-Performance Liquid Chromatography (HPLC) & LC-MS/MS: Clinical and research laboratories quantify alanine concentrations in plasma, urine, and cerebrospinal fluid using liquid chromatography coupled with tandem mass spectrometry. Derivatization techniques (e.g., using phenylisothiocyanate or o-phthalaldehyde) allow precise separation and quantification of alanine against stable-isotope-labeled internal standards (e.g., [13C3, 15N]L-alanine).
- Enzymatic Spectrophotometric Assays: Alanine concentrations can be determined spectrophotometrically using ALT coupled with lactate dehydrogenase (LDH). In this assay, ALT reacts with alanine and alpha-ketoglutarate to produce pyruvate and glutamate. Concurrently, LDH reduces the generated pyruvate to lactate while oxidizing NADH to NAD+. The stoichiometric decrease in optical absorbance at 340 nm directly correlates with the initial concentration of alanine.
- Nuclear Magnetic Resonance (NMR) Metabolomics: Proton NMR (1H-NMR) spectroscopy identifies alanine via a characteristic doublet resonance centered at approximately 1.48 ppm (corresponding to the methyl protons coupling with the alpha-proton) and a multiplet at 3.78 ppm (the alpha-methine proton). This enables label-free metabolomic quantification in biofluids and intact tissue specimens.
- Serum Alanine Aminotransferase (ALT) Activity: Rather than measuring alanine directly, standard medical biochemistry panels quantify serum ALT activity. Because ALT is predominantly localized within hepatocyte cytoplasm, acute or chronic hepatocellular necrosis causes the enzyme to leak into systemic circulation, making elevated serum ALT one of the most widely used markers of liver injury.
10. Applications & Practical Significance
Alanine plays prominent roles across multiple translational disciplines, including clinical hepatology, molecular therapeutics, industrial biotechnology, and athletic performance.
In clinical medicine, alanine flux is intrinsically tied to metabolic pathology. Beyond diagnostic utility in inborn errors of metabolism, perturbations in alanine levels are observed in non-alcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus, and cancer cachexia. In oncological settings, specific aggressive malignancies—notably pancreatic ductal adenocarcinoma (PDAC)—rely on extracellular alanine derived from tumor-associated pancreatic stellate cells as a key carbon source to fuel mitochondrial tricarboxylic acid (TCA) cycles and lipid biosynthesis, bypassing classic nutrient dependencies.
In sports science and nutrition, beta-alanine supplementation has gained widespread empirical support as an ergogenic aid. Beta-alanine serves as the rate-limiting substrate in the intramuscular synthesis of carnosine (beta-alanyl-L-histidine). Intracellular carnosine acts as a physiological physicochemical buffer, neutralizing hydrogen ions (H+) generated during high-intensity anaerobic glycolysis. By elevating muscle carnosine content through sustained dietary beta-alanine administration, athletes can attenuate exercise-induced intracellular acidosis, delaying neuromuscular fatigue during high-intensity exertion lasting between one and ten minutes.
In pharmaceutical engineering and biotechnology, alanine is used in recombinant mammalian cell culture media (e.g., Chinese Hamster Ovary [CHO] cells) to optimize monoclonal antibody yield and modulate ammonium accumulation. Furthermore, the synthesis of therapeutic peptidomimetics frequently integrates D-alanine or synthetic alanine analogs to enhance the proteolytic resistance and bioavailability of bioactive peptides in vivo.
11. Research & Empirical Evidence
Modern empirical research on alanine focuses on its systems-level signaling capacity, cellular metabolic reprogramming, and therapeutic targeting.
A seminal empirical breakthrough occurred when Felig et al. (1970) quantified arteriovenous differences across splanchnic and deep muscle vascular beds in healthy human subjects. Their work demonstrated that while alanine constitutes only approximately 7% to 10% of amino acid residues in skeletal muscle proteins, it accounts for more than 30% of total amino acid release from peripheral tissues into circulation during the post-absorptive state. This disparity provided conclusive empirical evidence that alanine is synthesized de novo within muscle through transamination before participating in hepatic gluconeogenesis.
In cancer metabolism, Sousa et al. (2016) demonstrated that pancreatic ductal adenocarcinoma cells systematically reprogram their microenvironment to acquire metabolic substrates. Using isotope-tracing mass spectrometry, the authors revealed that pancreatic stellate cells secrete alanine via autophagy in response to signaling cues from adjacent cancer cells. The malignant cells import this exogenous alanine via specific solute carriers, using its carbon skeleton to feed the TCA cycle for de novo lipid and non-essential amino acid synthesis, maintaining proliferative capacity in a nutrient-depleted, hypoxic tumor microenvironment.
Additional empirical research has evaluated the ergogenic efficacy and safety of beta-alanine. A comprehensive meta-analysis by Hobson et al. (2012), synthesizing dozens of randomized, double-blind, placebo-controlled trials, confirmed that chronic supplementation with beta-alanine (typically 3.2 to 6.4 g/day over a 4-week period) significantly improved exercise capacity during high-intensity tasks, establishing an empirical foundation for its use in sports nutrition.
12. Cultural & Cross-Cultural Considerations
Because alanine is endogenously synthesized by human cells from standard glycolytic intermediates, it is categorized as a nutritionally non-essential amino acid. Consequently, primary nutritional deficiency syndromes (analogous to kwashiorkor or essential amino acid deficiencies) do not occur specifically from dietary alanine insufficiency, regardless of dietary pattern.
Nonetheless, total dietary alanine intake varies considerably across different cultural dietary frameworks. Omnivorous diets rich in animal proteins (such as meat, poultry, seafood, dairy, and eggs) provide high quantities of preformed alanine. Conversely, populations consuming strictly plant-based diets derive alanine from legumes, cereals, and cruciferous vegetables, in which alanine concentrations are generally lower. Because human metabolic machinery maintains robust transamination capacity, individuals consuming balanced vegetarian or vegan diets maintain normal plasma alanine pools and glycogen reserves without adverse functional consequences.
In the context of traditional culinary traditions and sensory gastronomy, alanine—alongside glutamic acid and glycine—is known to elicit subtle umami and sweet taste sensations by interacting with heterodimeric T1R2/T1R3 and T1R1/T1R3 taste receptors on human lingual papillae. In several East Asian food cultures, the presence of free amino acids, including alanine, generated through natural food fermentation (e.g., in soy sauces, miso, and fermented fish pastes) is recognized as a key contributor to the rich sensory profile of traditional cuisine.
13. Criticisms, Debates & Limitations
Despite centuries of scientific consensus on its fundamental chemistry, several biochemical debates and clinical complexities involve alanine:
A persistent theoretical debate centers on the limitations of rigid amino acid categorizations. While canonically categorized as “non-essential,” alanine may become conditionally essential during extreme catabolic states, extensive burn injuries, sepsis, or advanced liver failure. Under such critical illness conditions, the rate of endogenous alanine biosynthesis and subsequent Cahill cycle flux may fall short of systemic metabolic demands for nitrogen disposal and gluconeogenic support, raising discussions regarding whether specialized clinical parenteral nutrition should be supplemented with alanine dipeptides (e.g., alanyl-glutamine).
Another debate concerns the use of serum alanine aminotransferase (ALT) activity as a surrogate biomarker for hepatic disease. Although ALT is clinically utilized as a primary screening parameter, its elevation is not exclusively liver-specific. Significant muscle trauma (rhabdomyolysis), prolonged strenuous exercise, or myocardial infarction can release peripheral ALT into the bloodstream, potentially leading to misdiagnosis of primary liver pathology. Furthermore, patients with advanced non-alcoholic steatohepatitis (NASH) or established cirrhosis can occasionally present with normal serum ALT levels, underscoring the clinical limitations of relying solely on this transaminase without imaging or histology.
In sports nutrition, high-dose administration of beta-alanine often triggers transient paresthesia—a harmless neuropathic sensation characterized by tingling and prickling across the skin, particularly the face and hands. While extensive investigations confirm that this phenomenon is caused by the activation of sensory neuron-specific G-protein-coupled receptors (MrgprD) and does not reflect neurotoxicity, it remains a frequent cause of patient concern and non-compliance in supplemental regimens, often requiring split-dosing or sustained-release formulations.
14. Related Terms & Distinctions
To prevent conceptual confusion, alanine must be differentiated from structurally related molecules, enzymes, and metabolic intermediates:
- Alanine vs. Pyruvate: Pyruvate is a 3-carbon alpha-keto acid that forms the end product of glycolysis. Alanine is the direct amino acid analogue of pyruvate; their structures differ solely by the presence of an amino group (-NH2) on alanine’s alpha-carbon versus a ketone oxygen (=O) on pyruvate.
- L-Alanine vs. Beta-Alanine: L-Alanine is an alpha-amino acid that is directly incorporated into proteins during translation. Beta-alanine is a structural isomer with the amine situated on the beta-carbon; it is non-proteinogenic and functions primarily as a building block for carnosine.
- Alanine vs. Glycine: Glycine is the simplest amino acid, possessing a single hydrogen atom as its side chain, making it the only non-chiral canonical amino acid. Alanine features a methyl group (-CH3), introducing chirality and hydrophobic character.
- Alanine vs. Alanine Aminotransferase (ALT): Alanine is a small metabolic substrate (a small-molecule amino acid), whereas ALT is a large catalytic enzyme (protein) that uses pyridoxal phosphate to transfer the amino group of alanine to alpha-ketoglutarate.
- Alanine vs. Serine: Serine is structurally identical to alanine except that one hydrogen of the methyl side chain is substituted with a hydroxyl group (-OH), converting an aliphatic, nonpolar amino acid into a polar, uncharged, hydrophilic residue capable of participating in enzymatic catalysis and phosphorylation.
15. Summary / Key Takeaways
Alanine represents a cornerstone of molecular architecture and human physiology. The essential concepts governing this amino acid include:
- Alanine is an aliphatic, nonpolar, non-essential alpha-amino acid containing a simple methyl (-CH3) side chain.
- Due to its minimal steric bulk, alanine displays the highest alpha-helical propensity among all canonical amino acids, stabilizing secondary structural elements throughout the proteome.
- Through the glucose-alanine (Cahill) cycle, alanine coordinates inter-organ nitrogen transport from peripheral skeletal muscle to the liver, concurrently fueling hepatic gluconeogenesis and facilitating safe nitrogen disposal via the urea cycle.
- Reversible transamination between alanine and pyruvate is catalyzed by alanine aminotransferase (ALT), a key diagnostic biomarker in clinical hepatology.
- Its non-proteinogenic isomer, beta-alanine, acts as the rate-limiting precursor for intra-muscular carnosine synthesis, functioning as an ergogenic buffer against exercise-induced acidosis.
- Alanine scanning mutagenesis remains a gold-standard methodological technique for interrogating the energetic contributions of specific amino acid residues to protein structure, receptor binding, and catalytic efficiency.
Ultimately, alanine’s structural simplicity belies its diverse biological significance. From its roles in protein folding and experimental mutagenesis to its coordination of whole-body nitrogen clearance and gluconeogenesis, alanine remains a foundational molecule in cellular biochemistry and systemic metabolic physiology.
References
- Felig, P. (1973). The glucose-alanine cycle. Metabolism, 22(2), 179–207. https://doi.org/10.1016/0026-0495(73)90269-2
- Hobson, R. M., Saunders, B., Ball, G., Harris, R. C., & Sale, C. (2012). Effects of β-alanine supplementation on exercise performance: A meta-analysis. Amino Acids, 43(1), 25–37. https://doi.org/10.1007/s00726-011-1200-z
- Sousa, C. M., Biancur, D. E., Wang, X., Halbrook, C. J., Sherman, M. H., Zhang, L., Christofk, H. R., & Kimmelman, A. C. (2016). Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion. Nature, 536(7617), 479–483. https://doi.org/10.1038/nature19084
- Strecker, A. (1850). Ueber die künstliche Bildung der Milchsäure und einen neuen, dem Glycocoll homologen Körper. Annalen der Chemie und Pharmacie, 75(1), 27–45. https://doi.org/10.1002/jlac.18500750103
- Wells, J. A. (1991). Systematic mutational analyses of protein-protein interfaces. Methods in Enzymology, 202, 390–411. https://doi.org/10.1016/0076-6879(91)02020-f