title: Scavenger receptor for aldehyde-modified proteins.
abstract: This paper describes an unexpectedly broad ligand specificity of a scavenger receptor of sinusoidal liver cells that is responsible for endocytic uptake of formaldehyde-treated bovine serum albumin (f-Alb). Binding of 125I-f-Alb to the isolated cells was effectively inhibited by bovine serum albumin (BSA) modified with aliphatic aldehydes such as glycolaldehye, DL-glyceraldehyde, and propionaldehyde whereas albumin preparations modified by aromatic aldehydes such as pyridoxal, pyridoxal phosphate, salicylaldehyde, and benzaldehyde did not affect this binding process. Binding of 125I-glycolaldehyde-treated BSA to the cells exhibited a saturation kinetics with an apparent Kd = 3.3 micrograms of the ligand/ml. This binding process was inhibited by unlabeled f-Alb as well as by the antibody raised against the f-Alb receptor. Indeed, 125I-glycolaldehyde-treated BSA underwent a rapid plasma clearance (t1/2 approximately 2 min) which was markedly retarded by unlabeled f-Alb. Upon treatment by these aldehydes, other proteins such as ovalbumin, soybean trypsin inhibitor, and hemoglobin were also converted to active ligands for the f-Alb receptor, while no ligand activity was generated with gamma-globulin and RNase A. These results clearly show that the f-Alb receptor, originally described as being specific for f-Alb, exhibits a broad ligand specificity in terms of both aldehydes and proteins and, hence, should be described as a scavenger receptor for aldehyde-modified proteins.
mesh_terms: D000079:Acetaldehyde / Q000031:analogs & derivatives / Q000494:pharmacology; D000447:Aldehydes / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D055598:Chemical Phenomena; D002621:Chemistry; D005557:Formaldehyde / Q000378:metabolism; D005985:Glyceraldehyde / Q000494:pharmacology; D007158:Immunologic Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017457:Receptors, Albumin; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism*
chemical_list: D000447:Aldehydes; D017457:Receptors, Albumin; D011956:Receptors, Cell Surface; C044105:formaldehyde-serum albumin; C044106:formaldehyde-serum albumin receptor; D005557:Formaldehyde; D012710:Serum Albumin, Bovine; D005985:Glyceraldehyde; C005556:propionaldehyde; D000079:Acetaldehyde; C010972:glycolaldehyde