Hydroxylysine kinase (HYKK)

Hydroxylysine kinase (HYKK) is an enzyme (EC 2.7.1.81) that catalyzes the phosphorylation of 5-hydroxy-L-lysine using GTP as a phosphate donor, forming GDP and 5-phosphonooxy-L-lysine[2][3]. It is encoded by the HYKK/AGPHD1 gene in humans[3][4]. This enzyme participates in the catabolism of hydroxylysine, a modified amino acid generated during collagen breakdown, and primarily functions in liver and kidney[3]. Deficiencies in hydroxylysine kinase are linked to rare inherited metabolic disorders such as hydroxylysinuria and hydroxylysinemia, with some patients displaying neurological symptoms, though disease causality remains under study[3]. Currently, hydroxylysine kinase is not a direct drug target and has no established interacting small molecules, but it is important in amino acid and connective tissue metabolism[2][3][4].

Other names

Guanosine triphosphate:5-hydroxy-L-lysine O-phosphotransferaseGTP:5-hydroxy-L-lysine O-phosphotransferaseHydroxylysine kinase (phosphorylating)

Catalyzes the GTP-dependent phosphorylation of 5-hydroxy-L-lysine, forming 5-phosphonooxy-L-lysine[2][3]