Homoarginine, the methylene homologue of arginine,as a substrate of human arginine:glycine amidinotransferase and arginases

Bûlleten' Sibirskoj Mediciny

T. F. Subbotina¹  A. A. Zhloba²  E. S. Alekseevskaya² 

[1] V.A. Almazov Federal North-West Medical Research Centre.;Academician I.P. Pavlov First St. Petersburg State Medical University;

关键词: homoarginine;    arginine:glycine amidinotransferase;    arginase;    creatine;    guanidinoacetic acid;   

DOI  :  10.20538/1682-0363-2018-1-7-14

来源: DOAJ

【 摘 要 】

L-homoarginine (hArg) is a non-coding amino acid, the blood level reduction of which is associated with an increased risk of stroke and heart attack. In humans and animals, hArg is mainly formed during the reaction catalyzed by the enzyme of the metabolic pathway of creatine biosynthesis:arginine: glycine amidotransferase (AGAT, EC 2.1.4.1), in the case where L-lysine acts instead of glycine as an acceptor of the arginine amidine group. It has been shown that hArg can serve for nitric oxide biosynthesis which is seemed a single significant enzymatic pathway established for hArg.The aim of this study was to investigate hArg as a substrate human AGAT and arginases.Materials and methods. In experiments with recombinant enzymes we established that Km for hArg in the reaction catalyzed by AGAT towards the formation of guanidinoacetic acid is 12.0 ± 1.1 mM. In reactions catalyzed by both types of arginase activity against hArg, unlike arginine, was not detected.Conclusions. Thus, the present study established that hArg may be considered as a substrate of AGAT additionally to nitric oxide synthases. Metabolic value of hArg, in addition to regulation of vascular tone, can be associated with cell energy metabolism. According to our data a decrease of hArg blood levels in cardiovascular diseases appears to be unrelated to a detectable increase of arginase activity.

【 授权许可】

Unknown