[Multiple forms of rat liver arginase].
Two differently charged isoforms of arginase were isolated from rat liver and partially purified. The isoelectric point for isoform I possessing more than 90% of the total arginase activity lies around 9.3, while that for isoform II lies around pH 7.0. Both isoforms have similar molecular weights (120,000) and close Km values (1-3 mM). In order to stabilize the enzyme activity both isoforms were obtained in an immobilized state. Study of the effects of some cholate compounds, SH-reagents and inhibitors on soluble and immobilized isoforms revealed some differences in the properties of these isoforms. Isoform II subunits are more tightly bound to Mn2+ than those of isoform I; the role of SH-groups in manifestation of the catalytic activity of the isoforms appears to be different. Isoform I possessing a positive charge (this is in agreement with the literary data) can be related to ureothelic enzymes, while isoform II is close to non-ureothelic arginases from brain and kidney not coupled with the ammonium detoxication mechanism.
D000818:Animals; D001119:Arginase / Q000302:isolation & purification* / Q000378:metabolism; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D046911:Macromolecular Substances; D008970:Molecular Weight; D051381:Rats
D007527:Isoenzymes; D046911:Macromolecular Substances; D001119:Arginase
Mnozhestvennye formy arginazy pecheni krysy.