Cellular retinol-binding protein difference

Retinaldehyde, when bound to retinol binding protein II (CRBPII), serves as a substrate for retinal reductase resulting in the production of retinol (14), which then binds to cellular retinol binding protein (CRBP) forming holo-CRBP. Holo-CRBP seems to be the preferred substrate for an esterification reaction (Fig. 7.6) mediated by lecithin retinol acyl transferase (LRAT), a microsomal enzyme that uses acyl groups donated from phosphatidylcholine (14).In cells not expressing CRBP, retinol esterification is carried out by a different enzyme, acyl CoArretinol acyl transferase (ARAT). 

Suruga, K., T. Goda, M. Igarashi, et al. 1997. Cloning of Chick Cellular Retinol-Binding Protein, Type II and Comparison to That of Some Mammals Expression of the Gene at Different Developmental Stages, and Possible Involvement of Rxrs and Ppar. Comp Biochem Physiol A Physiol 118, no 3 859-69. 

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