Molecular identification of hydroxylysine kinase and of ammoniophospholyases acting on 5-phosphohydroxy-L-lysine and phosphoethanolamine.

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Veiga-da-Cunha M, Hadi F, Balligand T, Stroobant V, Van Schaftingen E

Molecular identification of hydroxylysine kinase and of ammoniophospholyases acting on 5-phosphohydroxy-L-lysine and phosphoethanolamine.

J Biol Chem. 2012 Mar 2;287(10):7246-55. doi: 10.1074/jbc.M111.323485. Epub 2012 Jan 12.

PubMed ID

22241472 [ View in PubMed

]

Abstract

The purpose of the present work was to identify the catalytic activity of AGXT2L1 and AGXT2L2, two closely related, putative pyridoxal-phosphate-dependent enzymes encoded by vertebrate genomes. The existence of bacterial homologues (40-50% identity with AGXT2L1 and AGXT2L2) forming bi- or tri-functional proteins with a putative kinase belonging to the family of aminoglycoside phosphotransferases suggested that AGXT2L1 and AGXT2L2 acted on phosphorylated and aminated compounds. Vertebrate genomes were found to encode a homologue (AGPHD1) of these putative bacterial kinases, which was therefore likely to phosphorylate an amino compound bearing a hydroxyl group. These and other considerations led us to hypothesize that AGPHD1 corresponded to 5-hydroxy-L-lysine kinase and that AGXT2L1 and AGXT2L2 catalyzed the pyridoxal-phosphate-dependent breakdown of phosphoethanolamine and 5-phosphohydroxy-L-lysine. The three recombinant human proteins were produced and purified to homogeneity. AGPHD1 was indeed found to catalyze the GTP-dependent phosphorylation of 5-hydroxy-L-lysine. The phosphorylation product made by this enzyme was metabolized by AGXT2L2, which converted it to ammonia, inorganic phosphate, and 2-aminoadipate semialdehyde. AGXT2L1 catalyzed a similar reaction on phosphoethanolamine, converting it to ammonia, inorganic phosphate, and acetaldehyde. AGPHD1 and AGXT2L2 are likely to be the mutated enzymes in 5-hydroxylysinuria and 5-phosphohydroxylysinuria, respectively. The high level of expression of AGXT2L1 in human brain, as well as data in the literature linking AGXT2L1 to schizophrenia and bipolar disorders, suggest that these diseases may involve a perturbation of brain phosphoethanolamine metabolism. AGXT2L1 and AGXT2L2, the first ammoniophospholyases to be identified, belong to a family of aminotransferases acting on omega-amines.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Pyridoxal phosphate	5-phosphohydroxy-L-lysine phospho-lyase	Protein	Humans	Unknown	Cofactor	Details

Polypeptides

Name	UniProt ID
5-phosphohydroxy-L-lysine phospho-lyase	Q8IUZ5	Details