GLYCERALDEHYDE (synonym: glitseraldegid, aldotriose) — 2,3-dihydroxy-propanoic aldehyde, C 3 H 6 O 3 , the elementary optically active aldose; phosphate of glyceraldehyde is one of intermediate products of process glycolysis (see) and fermentations (see), G. and. exists in the form of two optical isomerides:
D-isomer (1) rotates the plane of the polarized beam to the right, [and] 20 D = +14 ° (in water); L-isomer (2) — to the left, [and] 20 L = — 14 ° (in water). Both isomers represent siropoobrazny liquids. Racemic substance crystallizes from methanol in the form of needles and prisms, t ° pl 69 — 70 °. And. it is capable to form dimeasures with t ° pl 132 — 142 °. Mix G. and. and dihydroxy acetone, turning out at oxidation of glycerin, carries the name of glycerose. And. let's well dissolve in water, it is bad in methanol, ethanol, ether. Unlike other monosaccharides, G. and. does not form cyclic forms (in water solutions) and glycosides. On spirit and aldehydic groups G. and. gives characteristic reactions, at its oxidation it is formed glyceric to - that, and at recovery — glycerin (see).
Receive G. and. by oxidation of acrolein hydrogen peroxide.
And. serves as the standard at establishment of a configuration of monosaccharides, and also alpha amino acids.
Glyceraldehyde, phosphoglyceric aldehyde and phosphoderivative the ketose corresponding to glyceraldehyde phosphodihydroxy acetone are products of the enzymatic reactions catalyzed by two zymohexases which are contained in tissues of animals and the person.
At acute infectious and toxic hepatitises in blood serum of patients in direct ratio of disease severity activity increases zymohexases (see); activity of these enzymes is increased also at acute psychoses, the progressing muscular dystrophy etc.
Practically all methods of definition of activity of zymohexases in blood serum are based on quantitative definition of G. and. or dihydroxy acetone which, connecting about 2,4 dinitrophenyl a hydrazine, form the hydrazones painted in alkaline condition; intensity of this coloring is proportional to activity of enzyme.
See also Carbohydrate metabolism .
Bibliography: Phytochemistry, the lane with English, under the editorship of V. L. Kretovich, M., 1968; Zbareky B. I., Ivanov I. I. and Mardashev S. R. Biological chemistry, page 81, 85, L., 1972; M and l of e r G. R. and Kordes Yu. G. Fundamentals of biological chemistry, the lane with English, M., 1970; Neni-ts e with to at K. D. Organic chemistry, the lane from Romanians., t. 2, M., 1963.
V. A. Popkov.