Fatty acid-binding site environments of serum vitamin D-binding protein and albumin are different.
Vitamin D-binding protein (DBP) and albumin (ALB) are abundant serum proteins and both possess high-affinity binding for saturated and unsaturated fatty acids. However, certain differences exist. We surmised that in cases where serum albumin level is low, DBP presumably can act as a transporter of fatty acids. To explore this possibility we synthesized several alkylating derivatives of (14)C-palmitic acid to probe the fatty acid-binding pockets of DBP and ALB. We observed that N-ethyl-5-phenylisooxazolium-3'-sulfonate-ester (WRK-ester) of (14)C-palmitic acid specifically labeled DBP; but p-nitrophenyl- and N-hydroxysuccinimidyl-esters failed to do so. However, p-nitrophenyl ester of (14)C-palmitic acid specifically labeled bovine ALB, indicating that the micro-environment of the fatty acid-binding domains of DBP and ALB may be different; and DBP may not replace ALB as a transporter of fatty acids.
Swamy
Narasimha
N
Bioorganic Chemistry & Structural Biology, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
Ray
Rahul
R
D000418:Albumins / Q000737:chemistry*; D001665:Binding Sites; D001692:Biological Transport; D002250:Carbon Radioisotopes; D005227:Fatty Acids / Q000378:metabolism*; D019308:Palmitic Acid / Q000378:metabolism; D014809:Vitamin D-Binding Protein / Q000737:chemistry*
D000418:Albumins; D002250:Carbon Radioisotopes; D005227:Fatty Acids; D014809:Vitamin D-Binding Protein; D019308:Palmitic Acid