THE MEMBRANE-ASSOCIATED 40 KD FATTY-ACID-BINDING PROTEIN (BERK PROTEIN), A PUTATIVE FATTY-ACID TRANSPORTER IS PRESENT IN HUMAN SKELETAL-MUSCLE

Muscle tissue (1.1 +/- 0.1 grams) was obtained from seven healthy indi viduals (3 males, 4 females) using an open incision approach before an d after ingestion of either 75 grams of dextrose (N=5) or water (N=2). Purified sarcolemmal membranes from the muscle were prepared using a sucrose step gradient. A polyclonal antibody raised against the purifi ed (99%) rat hepatocyte 40 KD membrane fatty acid binding protein (mFA BP-L*) was used to probe for this putative transporter in the muscle membranes using Western blot. A single band at the 40 KD MW band was i dentified which reacted antigenically with the protein purified from r at livers. The response of Berk's protein 60-75 minutes after dextrose ingestion (or water) was erratic and no specific trend could be ident ified. Our data demonstrate that the 40 KD mFABP-L originally isolated from rat liver is also present in human skeletal muscle membrane. Thi s protein may be involved in transport of fatty acids across the membr ane of skeletal muscle, however its physiological role in human fatty acid metabolism remains to be established.