= Lecithin retinol acyltransferase
<Lecithin retinol acyltransferase> is an <enzyme> that transfers an <acyl group> from <phosphatidylcholine>, also called lecithin, to <retinol>, producing a <retinyl ester>. The donor's position and the acceptor's alcohol group are part of the reaction definition; describing it merely as an enzyme that binds vitamin A would omit its chemical function.<Lecithin retinol acyltransferase in IUBMB Enzyme Nomenclature>[EC 2.3.1.135, accepted reaction and sn-1 acyl transfer]{ref}
This reaction supplies ester forms for <retinoid> storage and metabolism. It is distinct from changing retinyl-chain geometry, even though both operations occur in the broader <visual cycle>.<Lecithin retinol acyltransferase in IUBMB Enzyme Nomenclature>[Comments, ester products and substrate recognition]{ref}
A 2005 experiment illustrates why the distinction matters. Cultured cells expressing <RPE65> required coexpression of <lecithin retinol acyltransferase> to provide the ester substrate for the measured production of <11-cis-retinol>.<RPE65 is the isomerohydrolase in the retinoid visual cycle by Gennadiy Moiseyev and others>[Abstract, coexpression requirement]{ref} Missing product can therefore reflect a failure of upstream substrate supply rather than a failure of the downstream enzyme itself. Measuring both steps helps distinguish a pathway requirement from the identity of the catalyst performing a particular transformation.
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