ARGINASE

From Big Medical Encyclopedia
ARGINASE (L - arginine - ureogidrolaza; K.F.3.5.3.1) — enzyme about a pier. it is powerful apprx. 140 000, catalyzing splitting of arginine on ornithine and urea:

Metabolic role And. consists in closing of the circuit of transformation of nitrogen of amino acids in urea (see). It is richest And. liver of mammals, including and person, and also amphibians and sea fishes. At mammals And. contains in l the drawing-up mammary gland, a brain, it is less in a mucous membrane of intestines, kidneys, seed plants. Traces And. are found in all fabrics. And. it is found also at some invertebrates, napr, in digestive gland of land and fresh-water Castropoda, and also in fabrics of various plants. And. it is not found in a liver of birds and reptiles (except for a turtle). Activity And. a liver raises at proteinaceous food and especially at parenteral administration of arginine; at preferential food by carbohydrates — it is lowered.

And. it is easily taken by aqueous salt solutions or the diluted glycerin. And. it is received in a crystal look. Activity And. raises in the presence of ions of Mn 2+ , With 2+ , Ni 2+ , Cd 2+ . A role of the natural activator is played by ions of Mn 2+  ; reduction of contents in food of manganese sharply reduces A. Aktivnost's activity of enzyme falls also during removal of a hypophysis and adrenal glands. The injection of corticosterone, 11 dehydrocorticosterone or 11-degidro-17-oxycorticosterone recovers

A. A. activity is characterized by strict specificity: effect of enzyme requires existence of free carboxyl and guanidinovy groups. The quantity is accepted to an activity unit And., a cut in 1 min. at t ° 25 °, pH 9,5 and concentration of substrate, the equal 0,285 M, form 1 mmol of urea.

See also Ornitinovy cycle , Tricarboxylic acids cycle .


Bibliography: Braunstein A. E. Biochemistry of amino-acid exchange, page 237, M., 1949; Greenberg D. M of Arginase, in book: Enzymes, ed. by P. D. Boyer and. lake, v. 4, p. 257, N. Y. — L., 1960, bibliogr.

Η. P. Meshkova.

Яндекс.Метрика