#metabolism

• Alkaptonuria — A rare hereditary disorder of aromatic amino acid metabolism (phenylalanine and tyrosine), inherited in an autosomal recessive pattern, caused by a deficiency of the homogentisate 1,2-dioxygenase enzyme. This congenital structural anomaly leads to the accumulation of homogentisic acid (alkapton) in the body, which is excreted in the urine (turning it black upon exposure to air) and deposits in connective tissues and cartilages, causing ochronosis and severe arthropathies in adulthood.
• Aldolase — An enzyme belonging to the lyase class that catalyzes the reversible cleavage of fructose-1,6-bisphosphate into two triose phosphates (glyceraldehyde-3-phosphate and dihydroxyacetone phosphate), a core step in the glycolytic pathway. Clinical measurements of its serum levels are utilized to diagnose acute muscle or hepatic disorders.
• Aleuronat — A dietary food preparation in the form of coarse flour or powder, industrially manufactured by artificially enriching cereal flour with proteins extracted from the aleurone layer (gluten and phytoglobulins). It is widely used in specialized nutrition and in manufacturing hypoglycemic products intended for patients suffering from diabetes or metabolic disorders, due to its massive nitrogen supply and extremely low carbohydrate content.
• Allobiosis — A physiological state or form of existence of a living organism characterized by adaptation or reaction to an artificially modified, unnatural environment or one completely different from its native one. In experimental ecology, the term describes the structural response of tissues or cellular communities when forced to survive under non-standard biochemical parameters, demonstrating the metabolic plasticity of the system.
• Allostery — A biochemical phenomenon or structural property of certain proteins (specifically enzymes and receptors) whereby the binding of an effector molecule (ligand) at a specific site (allosteric site) indices a spatial conformational change in another area of the molecule, directly altering its affinity and biological activity at the active site.
• Amphibolic — Containing amphiboles or belonging to them; in petrography, it describes a rock or mineral structure dominated by the presence of inosilicates from the amphibole group. In biochemistry and physiology, the term describes a dual or hybrid metabolic pathway (such as the Krebs cycle) that functions structurally in both catabolic (breakdown) and anabolic (synthesis) processes.
• Amidase — An enzyme belonging to the hydrolase class that catalyzes the hydrolytic cleavage of a linear amide bond, converting an amide compound into a carboxylic acid and ammonia or a corresponding amine. This biocatalyst plays an essential structural role in nitrogen metabolism, cellular detoxification processes, and industrial biocatalysis used for the enantioselective synthesis of high-purity pharmaceutical compounds.
• Amylogenesis — The biochemical process of formation and biosynthesis of starch within plant cells. Amylogenesis takes place inside the amyloplasts through the successive polymerization of glucose molecules, being an essential structural metabolic stage for storing energy derived from photosynthesis.
• Amylolysis — The biochemical process of decomposition, cleavage, and hydrolysis of starch into structural compounds with a lower molecular weight, such as dextrins, maltose, and glucose. This degradative reaction is catalyzed by specific enzymes called amylases and takes place naturally during digestion in animals and humans, as well as in the germination process of seeds or in various fermentative industries.
• Amyloplastic — Pertaining to amyloplasts or relating to them; concerning the activity of forming and storing starch within specialized plant cell organelles. It is used to describe metabolic processes, membrane structures, or cytoplasmic changes correlated with the physiology of these specialized plastids.
• Amino acid — An organic compound with a mixed function, containing in its molecule one or more amino groups (-NH2) and carboxyl groups (-COOH). These structural compounds are the fundamental building blocks of proteins, classified into essential (which cannot be synthesized by the organism and must be provided by diet) and non-essential, playing a crucial role in cellular metabolism, enzyme synthesis, and nerve impulse transmission.
• Aminopeptidase — An enzyme of the exopeptidase class that catalyzes the specific hydrolysis of peptide bonds at the free N-terminal end of a polypeptide chain, successively releasing terminal amino acids. This biocatalyst plays an essential structural role in the final phases of protein digestion within the intestinal mucosa, as well as in intracellular protein degradation and recycling processes.
• Anabolic — Stimulating or pertaining to anabolism; a metabolic process of biosynthesis through which the organism transforms simple nutrients into complex cellular compounds (proteins, muscle tissue), consuming energy. As a neuter noun (in plural, anabolic steroids), it designates synthetic substances or hormones used medically for recovery or, improperly in sports, for fast muscle mass gain.
• Anabolism — A fundamental phase of metabolism, characterized by the totality of biochemical processes of assimilation and biosynthesis through which the organism transforms simple nutrients from the environment into complex macromolecular compounds (proteins, nucleic acids, glycogen, and tissues). This cellular structural phenomenon requires a direct consumption of chemical energy, supplied by the breakdown of ATP molecules.
• Anabolite — A chemical substance, molecule, or organic compound directly resulting from a process of anabolism or used as a precursor in cellular biosynthesis reactions. It represents the structural building block used by the cell for energy storage or macromolecule formation, being the opposite of a catabolite.
• Anabolic agent — Having the property of stimulating anabolism, favoring protein synthesis and tissue growth, particularly muscle mass. As a neuter noun, it designates a steroidal drug or a chemical synthetic compound used in medical therapy to combat muscle wasting or severe malnutrition states and, abusively, in bodybuilding or sports as a doping agent.
• Anaerobiosis — A form of life, condition, or mode of existence of certain microorganisms that structurally develop in an environment completely devoid of free molecular oxygen. This biological phenomenon forms the basis of archaic energy metabolism processes, being essential in various isolated ecosystems, wastewater treatment (anaerobic digestion), and food fermentation industries.
• Anaerobiont — A microorganism or lower organism that lives and structurally develops exclusively in an environment devoid of free molecular oxygen. This type of organism, primarily represented by denitrifying, methanogenic, or sulfate-reducing bacteria, obtains the energy required for its vital functions through alternative metabolic processes such as fermentation or anaerobic respiration.
• Anastasis — A latent biological state or process of restoring vital functions after a period of suspended animation, temporary asphyxia, or apparent clinical death; it represents the active transition phase wherein an organism resumes normal metabolism. Narrowly in histology or pathology, the term describes the temporary arrest of cellular degradation followed by structural tissue regeneration.
• Androgalactosemia — An extremely rare hereditary metabolic condition manifested exclusively in male patients, characterized by the organism's structural inability to correctly metabolize galactose due to a specific enzyme deficiency linked to the X chromosome or influenced by androgen hormones, leading to toxic compounds accumulation.