From Big Medical Encyclopedia

ALANINE (α-lactamic acid acid; SN 3 - CH(NH 2 ) - SOON) — one of amino acids playing a large role in a metabolism; is a part of various proteins, meets also in a stand-at-ease.

And. is the elementary optically active amino acid; the majority of other natural amino acids can be considered as derivatives And., in which one hydrogen atom at the third carbon atom of a chain is replaced with this or that radical. Natural And. treats a L-row; rotates the plane of polarization to the right: [α] D = +13,0 ° in 5,0 N NSL solution at t ° 25 ° and +1,6 ° — in water. And. let's well dissolve in water, it is bad — in alcohol and it is not ether-soluble at all; melts with decomposition at t ° 297 °.

Left-handed (D-isomer) And. meets as a part of mukopeptid of a cell wall of some bacteria.

β-alanine (NH 2 CH 2 • CH 2 • SOON) optically is inactive. In the nature β-alanine meets hl. obr. as a part of peptides of carnosine (see) and anserine (see), and also pantothenic to - you and a coenzyme And., is more rare in a free look.

β-alanine melts at t ° 196 °, we will very well dissolve in water. In an organism it is formed at decarboxylation asparaginic to - you or at the disintegration of uracil going through dihydrouracil (see. Pirimidinovy bases ).

And. is among so-called replaceable amino acids (see) and it can be synthesized in a human body and animals. Forming as a result of reactions of interamination (see) and deaminations (see) pyroracemic to - that, And. joins in a citrate tricarbonic acid cycle (see. biological oxidation ). And. is one of intermediate products of a metabolism and through pyruvic acid (see) can turn into other amino acids: series, valine, a leucine, an isoleucine, etc. Besides, in the course of exchange And. it can be formed from asparaginic to - you and of kynurenine. Carbon skeleton And. it is used in an organism for synthesis of fats and carbohydrates. Anti-ketogenic action is connected with it And. and other amino acids at diabetes or long starvation (see. Ketone bodies ).

Definition And. carry usually out along with other amino acids by methods chromatography (see). Specific methods of definition And. are based on deamination its nitrogenous to - that and definition formed milk to - you or on oxidation And. to acetic aldehyde and definition of the last.

Bibliography: Grinstein D. and Vinits M. Himiya of amino acids and peptides, the lane with English, M., 1965.

I. B. Zbarsky.