IMINO-ACIDS

From Big Medical Encyclopedia

IMINO-ACIDS - the organic acids containing iminogroup (= NH), are a part of proteins; genetically caused disturbance of exchange of some of them at the person is the reason of hereditary diseases (e.g., giperprolinemiya and oksiprolinemiya).

On the properties I. are close to to amino acids (see), and as a result of catalytic hydrogenation And. turn into amino acids. Depending on position of iminogroup in a molecule I. in relation to COOH group distinguish alpha, beta, gamma etc. imiiokislota.

And. can be received by effect of ammonia on ketonic acids. alpha Imino-acids which molecule is constructed on type , are intermediate products of oxidizing deamination of amino acids (see. Deamination ).

Are biologically important heterocyclic And. proline and oxyproline (see. Prolin ). And. give yellow coloring with ninhydrin, are a part of proteins and usually are considered as amino acids. The proteins rich with proline, - prolamines (see) and gliadines (see. Gliadine ) — are water-insoluble, but are well alcohol-soluble. Oxyproline contains only in the few proteins, hl. obr. in collagen (see), it is also formed of proline by a hydroxylation of the last in the course of biosynthesis of protein. In plants in a free look often meets pipecolic (piperidine-2-carboxylic) to - that (imino-acid), being a metabolite lysine (see). In juice of some plants also others are found And.

At genetic insufficiency at the person of enzyme of a prolineoxidase (KF 1.5.1.2) in blood serum the content of proline owing to blocking of reaction of its transformation in the delta '-pyrroline - 5 - carboxylat sharply increases. Oxidation of oxyproline in this case is not broken though the strengthened allocation with urine not only of proline, but also oxyproline is noted and glycine (see). At this disease disturbances from secretory system are noted and mental retardation though it is not clear in what measure they are a consequence of this anomaly of exchange.

At inborn disturbance of normal activity of an oxyprolineoxidase in blood serum and urine the content of oxyproline because of blocking of its turning into the delta' - pyrroline - 3 - oxy - 5 - carboxylat sharply increases. Exchange of collagen at the same time is not broken, the content of the peptide and connected oxyproline in urine remains within norm; exchange of proline, apparently, is also not broken. This anomaly of exchange is followed by sharply expressed mental retardation.


Bibliography: Grinstein Dzh. also Blame M. Himiya's c of amino acids and peptides, the lane with English, M., 1965; Efron M. L., In i x b at E. M and. P of at 1 e s G. V. Hyd-roxyprolinemia, New Engl. J. Med., v. 272, p. 1299, ^ 1965.

I. B. Zbarsky.

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