Acyl-CoA-binding protein (ACBP) and its relation to fatty acid-binding protein (FABP): an overview

Acyl-CoA-binding protein is a 10 Kd protein which binds medium- and long-chain acyl-CoA esters with high affinity. The concentration in liver is 2-4 times the acyl-CoA concentration. ACBP has much greater affinity for acyl-CoA than FABP. FABP from bovine heart and liver is unable to compete with multilamellar liposomes, Lipidex and microsomal membrane in binding acyl-CoA esters, whereas ACBP effectively extracts acyl-CoA from all those sources. Previously published results on the effect of FABP on acyl-CoA metabolism need to be reevaluated due to possible contamination with ACBP. Recently it was discovered that ACBP is identical to a putative neurotransmitter diazepam binding inhibitor. The possibility therefore exists that ACBP has more than one function.