Two histidine residues are essential for catalysis by lecithin retinol acyl transferase.
Lecithin retinol acyl transferase (LRAT) is a novel membrane bound enzyme that catalyzes the formation of retinyl esters from vitamin A and lecithin. The enzyme is both essential for vision and for the general mobilization of vitamin A. The sequence of LRAT defines it as a novel enzyme unrelated to any other protein of known function. LRAT possesses a catalytically essential active site cysteine residue. The enzyme also contains six histidine residues. It is shown here that two of these residues (H57 and H163) are essential for catalysis. A mechanistic hypothesis is presented to account for these observations.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
M S
MS
Mondal
A
A
Ruiz
J
J
Hu
D
D
Bok
R R
RR
Rando
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D002417:Cattle; D002478:Cells, Cultured; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism
D014801:Vitamin A; D006639:Histidine; D014212:Tretinoin; D000217:Acyltransferases; C056942:lecithin-retinol acyltransferase