Purification and structural studies of rabbit erythrocyte cytochrome b5.
A single form of cytochrome b5 has been isolated in highly purified form from the cytosolic fraction of rabbit erythrocytes by sequential chromatography on DE-52 cellulose, Sephadex G-75, and DEAE-Sephadex A50. The cytochrome is structurally similar to the N-terminal, heme-binding domain of rabbit liver microsomal cytochrome b5. Like the liver protein, it is blocked at the amino terminus. Its amino acid composition is similar to that of residues 1-97 of the microsomal protein. With one exception, tryptic peptides derived from apo-cytochrome b5 of rabbit erythrocytes co-elute with the tryptic peptides obtained from a soluble hemepeptide fragment of microsomal cytochrome b5. These findings, together with amino acid sequence analysis of the carboxyl terminal tryptic peptides, identify the erythrocyte cytochrome b5 as a 97-residue peptide.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003573:Cytochrome b Group / Q000097:blood* / Q000302:isolation & purification; D015786:Cytochromes b5; D003600:Cytosol / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits; D014357:Trypsin
D000596:Amino Acids; D003573:Cytochrome b Group; D010446:Peptide Fragments; D015786:Cytochromes b5; D014357:Trypsin