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Two histidine residues are essential for catalysis by lecithin retinol acyl transferase
Author(s) -
Mondal Madhu S,
Ruiz Alberto,
Hu Jane,
Bok Dean,
Rando Robert R
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)02428-5
Subject(s) - lecithin , chemistry , enzyme , transferase , histidine , active site , residue (chemistry) , biochemistry , cysteine , vitamin , stereochemistry
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.