Visualization of heparin-binding proteins by ligand blotting with 125I-heparin.
A ligand-blotting procedure which allows detection of heparin-binding proteins is described. Crude commercial heparin was fractionated by chromatography on a column of human plasma low-density lipoproteins immobilized to Sepharose CL-4B. Chromatography yielded an unbound and a bound fraction of heparin, designated URH and HRH, respectively. The HRH fraction was reacted with the N-hydroxysuccinimidyl ester of 3-(p-hydroxyphenyl)propionic acid and then labeled with 125I. Proteins were separated by 3-20% pore-gradient gel electrophoresis, transferred to nitrocellulose, and then assayed for their ability to bind 125I-labeled HRH. Human plasma apolipoproteins B-100, B-48, and E of chylomicrons, very low-density lipoproteins, and low-density lipoproteins bound the 125I-labeled HRH; the radiolabeled heparin did not bind to serum albumin, ferritin, catalase, and lactate dehydrogenase. The ligand-blotting procedure should facilitate the purification of heparin-binding domains from these proteins and, moreover, may be applicable to the investigation of heparin-protein interactions in general.
D001053:Apolipoproteins / Q000097:blood; D001055:Apolipoproteins B; D001057:Apolipoproteins E; D001345:Autoradiography; D002352:Carrier Proteins / Q000097:blood*; D055598:Chemical Phenomena; D002621:Chemistry; D006493:Heparin / Q000097:blood*; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008024:Ligands
D001053:Apolipoproteins; D001055:Apolipoproteins B; D001057:Apolipoproteins E; D002352:Carrier Proteins; D007457:Iodine Radioisotopes; D008024:Ligands; D006493:Heparin