McDowell J H, Nawrocki J P, Hargrave P A
Department of Ophthalmology, School of Medicine, University of Florida, Gainesville 32610.
Biochemistry. 1993 May 11;32(18):4968-74. doi: 10.1021/bi00069a036.
Bovine rhodopsin has been phosphorylated in rod outer segments by ATP and endogenous rhodopsin kinase. Mono-, di-, and triphosphorylated rhodopsins have been prepared by chromatofocusing. Nearly all of the phosphate is found in peptide 330-348, formed by digestion of phosphorhodopsins with endoproteinase Asp-N. Sequence analysis of the phosphopeptides shows that monophosphorylated rhodopsin consists of a mixture containing rhodopsins phosphorylated at 338Ser and 343Ser. Diphosphorylated rhodopsin is phosphorylated at both 338Ser and 343Ser. When rhodopsin becomes triphosphorylated it does not become phosphorylated on 334Ser but appears to become phosphorylated on one or more of the four threonine residues: 335Thr, 336Thr, 340Thr, and 342Thr.
牛视紫红质已在视杆外段被三磷酸腺苷（ATP）和内源性视紫红质激酶磷酸化。通过色谱聚焦法制备了单磷酸化、双磷酸化和三磷酸化的视紫红质。几乎所有的磷酸都存在于肽段330 - 348中，该肽段是由磷酸化视紫红质用天冬氨酸内肽酶（Endoproteinase Asp-N）消化形成的。磷酸肽的序列分析表明，单磷酸化视紫红质由在338位丝氨酸（Ser）和343位丝氨酸磷酸化的视紫红质混合物组成。双磷酸化视紫红质在338位丝氨酸和343位丝氨酸均被磷酸化。当视紫红质变为三磷酸化时，它在334位丝氨酸上未被磷酸化，而是似乎在四个苏氨酸残基中的一个或多个上被磷酸化：335位苏氨酸（Thr）、336位苏氨酸、340位苏氨酸和342位苏氨酸。
