LYSINE

From Big Medical Encyclopedia

LYSINE (α,ε-диаминокапроновая acid) — amino acid, irreplaceable in food of the person and animals, is molecular composition of proteins and peptides; genetically caused insufficiency of the nek-ry enzymes participating in exchange of a lysine in a human body is the reason of heavy pathology. In the lacrimal liquid and watery moisture of an anterior chamber of an eye of the person isomer L. — the beta lysine plays a role of an antibacterial factor. In a human body of L. arrives with food as a part of proteins of plant and animal origin; standard daily rate for the person — 1,6 g of L.

LYSINE (α,ε-диаминокапроновая acid)

L. exists in the form of two isomers: L-and D-lysine. The L-lysine and its oxyderivative — L-oxylysine is most widespread in the nature. The L-lysine is a part of many proteins. The maintenance of a lysine in histones (see) formed the basis of classification of these proteins. Contains in a myoglobin apprx. 16% of L., in seralbumins — 12,3%, in beta lactoglobulin — 11,4%, in ribonuclease — 10,5%, in fibrinogen — 9,2%, in hemoglobin — 8,5%, in casein — 8,2%, in a lysozyme — 5,7%, in kollagena — apprx. 5%, in keratins — 1 — 3%, in elastin — 0,5%. Contains in collagen also apprx. 1,5% of oxylysine.

Pier. weight (weight) of L. 146,19. Isoelectric point (see) is at pH 9 74; [a] D20 = +25,9 ° (2%; 6 N of HCl); + 7,6 ° (2,2%; 3 N of NaOH); + 13,5 ° (2%; H 2 O), t ° pl 224 — 225 ° (with decomposition). We will well dissolve a L-lysine in water, in to-takh, in alkalis, we will poorly dissolve in ethanol, it is insoluble on air. Of water solution drops out in the form of acicular crystals, of spirit solution — in the form of hexagonal plates.

The D-lysine has the same temperature of melting, [a]D24-26 =-25,9 ° (0,5 — 2%; 5 N of HCl) — 13,5 ° (0,5 — 2%; H 2 O).

L-oxylysine (α,ε-диамино-бета-оксикапроновая to - that) has a pier. weight (weight) 162,19; [a] D24 - 26 = +17, 8 (0, 5 — 2%; 5 N of HCl), +9,2 (0,5 — 2%; H 2 O)., L. and reactions, inherent for amino acids, give oxylysine: they interact with ninhydrin, 2,4 dinitrofluobenzene and other reagents, characteristic of amino acids. L. and oxylysine give specific staining reaction with furfural in acid medium. Compounds of these amino acids with picric and phosphomolybdenic to-tami are insoluble. From protein hydrolyzates L. and oxylysine are besieged in the form of picrates.

Quantitatively L. and oxylysine is determined by hromatografichesky methods, usual for all amino acids (see. Chromatography ). Besides, the specific method allowing to define amounts of these amino acids in hydrolyzates without preliminary chromatography is developed. The method is based on staining reaction with furfural.

In an organism of animals and the person. L. it is not synthesized. In vegetable organisms there are two ways of biosynthesis of L.: through diaminopimelic and through alpha and aminoadipinic to - you. Nitrogen entered to an experimental animal marked on nitrogen L. it is allocated in the form of an urea nitrogen; The D-lysine is allocated with urine in not changed look. In a human body the L-lysine turns as follows: 1) a lysine + + alpha ketoglutarate —> sakharopin —> semi-aldehyde alpha and aminoadipinic to - you + a glutamate —> alpha and aminoadipinic to - that; 2) a lysine —> gomoarginin; 3) a lysine —> gomotsitrullin; 4) a lysine —> pipecolic to - that; 5) lysine> ε-N-atsetillizin.

Contains in a blood plasma of the healthy person apprx. 3% of L. In days with urine at the person 7 — 48 mg of L are allocated. depending on the content of this amino acid in food.

In 1965 Mr. of H. Ghadimi et al. for the first time described a giperlizinemiya — the inborn disease inherited, apparently, on recessive type. It is connected with insufficiency a lysine ketoglutarate — the reductase catalyzing transformation of a lysine in sakharopin. The disease is shown in the early childhood by increase in maintenance of L. in cerebrospinal liquid, at loading of L. — unusual increase in content of this amino acid in blood, a lizinuriya, an adynamy, a growth inhibition and puberty, anemia, mental retardation, anomaly of pupils (a spherophakia and a strabismus). Restriction of L. in a diet does not yield positive takes. One of kollagenoz — Elers's syndrome — Danlosa is caused by inborn insufficiency of enzyme of a lysineoxidase. In urine of such patients products of degradation of collagen and elastin are found: glucosyl-galaktozil-oxylysine (35 nmols/days), galaktozil-oxylysine (45 nmols/days) and L - brought down-proline (33 nmols/days). In a pathogeny of a disease a part is played by disturbance of formation of stable cross bonds in collagenic fiber (see. Collagen ). Clinically the disease is shown by inborn heart disease (a syndrome of the «clapping» valve), low-tallness, flabby skin, nek-dig looseness of joints, tendency to formation of bruises (see. Desmogenez imperfect ).

Insufficiency of the enzymes participating in exchange of L., it can be usually established in culture of fibroblasts of the people suffering from hereditary diseases, the reason to-rykh genetic defect any a lysine - the turning enzyme is.



Bibliography: Pyatnitskaya I. N. and Vorobyova N. A. Definition of an available lysine for evaluation test of protein, Vopr, pitas., No. 3, page 3, 1977; D and p-with i s J. and. lake of Familial hyperlysinemia with lysine-ketoglutarate reductase insufficiency, J. clin. Invest., v. 48, p. 1447, 1969; FordL. C., De Lance R. J. a. Petty P. W. Identification of nonlysozymal bactericidal factor (beta lysin) of in human tears and aqueous humor, Amer. J. Ophthal., v. 81, p. 30, 1976; G h a d i m i H., Binnington U. I. a. Pecora P. Hyperlysinemia associated with retardation, New Engl. J. Med., v. 273, p. 723, 1965; P a t t h at M. a. P a t t h at A. Specific color reaction for the determination of lysine and/or ornithine, Acta biochim. biophys. Acad. Sci. hung., v. 10, p. 277, 1975.


L. P. Alekseenko.

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