Isoelectric focusing of phosphorylated cattle rhodopsin.
32P-rhodopsin was partially separated by isoelectric focusing into several fractions of different phosphorylation extent. It was found that the incorporated phosphate is not uniformly distributed in a population of rhodopsin molecules. In a preparation with an average phosphorylation extent of 2.4 moles of phosphate per mole of rhodopsin, most of the 32P-phosphate was found in fractions where 4-5 phosphates are bound per rhodopsin, whereas a large fraction of the total rhodopsin was not phosphorylated at all. The maximum number os phosphate binding sites in rhodopsin appears to be at least five.
D000818:Animals; D002417:Cattle; D007525:Isoelectric Focusing; D010710:Phosphates / Q000032:analysis / Q000378:metabolism; D010786:Photoreceptor Cells; D011485:Protein Binding; D012168:Retinal Pigments / Q000302:isolation & purification; D012243:Rhodopsin / Q000302:isolation & purification / Q000378:metabolism
D010710:Phosphates; D012168:Retinal Pigments; D012243:Rhodopsin