From Big Medical Encyclopedia

MALIC ACID [a synonym (hydras) hydroxy-butanedioic acid] — dicarbonic (hydras) of oxypussycats of lot NOOS —

— CH(OH) — CH2 — СООН, one of intermediate products of recycling at aerobic organisms — a cycle of tricarboxylic acids. Anion Ya. to. call malate.

I. to. is a product of the seventh reaction of a cycle of tricarboxylic acids (see. Tricarboxylic acids a cycle) catalyzed fumarating - hydratase (fumarase; KF, and substrate of the eighth, completing reaction of a cycle consisting in regeneration of its mother substance — oxalacetic acid (see) as a result of oxidation I. to. This reaction is catalyzed by a malate dehydrogenase (see), activity a cut can serve as additional diagnostic test at a number of diseases in blood serum and patol. processes (myocardial infarction, intravascular hemolysis, hepatitises, cirrhoses of a liver, diseases of bilious ways, etc.). In addition to a cycle of tricarboxylic

acids Ya. to. it can be formed of pyruvic acid (see). Reaction so-called «apple» enzyme [a malate dehydrogenase catalyzes (dekar-ooksiliruyushchy), pyruvate-malate — a carboxymanhole; KF—40]. This exchange reaction I. to. in an organism is of great importance since she allows to receive nicotinamide adenine dinucleotide (see) — a coenzyme in got into condition: L-ma-

of armor + NAD(F)+ pyruvate + C02 + + NAD(F)*N. If reaction proceeds in the opposite direction, it gives the chance to pyruvic acid (pyruvate) directly to enter a cycle of tricarboxylic acids, passing stages of oxidizing decarboxylation (see Decarboxylation) or a carboxylation to oxalacetic acid.

I. to. exists in the form of D-and L-isomers (see the Isomerism), in the nature meets generally L-apple to - that, contained in fruits of a mountain ash, apples, raspberry. For both isomers g°pl 100 °, for a racemate (see. Racemic connections) £ °pl 128 °. Apple to - that well a rastvorima in water and alcohol, it is bad — on air. Synthesize L-apple to - that splitting of a racemate tsinkhoniny or recovery of L - wines - ache to - you hydrogen iodide at 130 °. I. to. apply during the receiving various pharmaceuticals in pharmaceutical industry, in production of wines, fruit waters, confectionery.

Bibliography: Krebs G. A. and Korn -

e r G. L. Energy conversions in live systems, the lane with English, M., 1959; Metsler D. E. Biochemistry, the lane with English, t. 2, M., 1980; H and h and and -

and A. E N. Main beginnings of organic chemistry, t. 1, M., 1954.