The Partial Purification and Properties of Hydroxylysine Kinase from Rat Liver

Abstract

Abstract Hydroxylysine kinase (guanosine triphosphate:5-hydroxy-l-lysine O-phosphotransferase; EC 2.7.1.-) has been purified 1200-fold from rat liver and its properties partially elucidated. The enzyme catalyzes the phosphorylation of allohydroxy-l-lysine and hydroxy-l-lysine with an apparent Km ∼ 6 µm, but has no activity with either of the d isomers. The maximum velocity with allohydroxy-l-lysine was 1.5 to 3 times greater than with hydroxy-l-lysine. GTP or hypo-xanthine triphosphate, serve as the phosphate donor. Mg2+ is specifically required for the reaction while both Mn2+ and Zn2+ are inhibitory. The active phosphorylating agent appears to be the MgGTP2- complex with guanosine diphosphate as the nucleotide product. The kinase is present in the liver or kidney, or both, of rats, mice, chickens, bovine, rabbits, and two species of primates.