Wilson J M, Landa L E, Kobayashi R, Kelley W N
J Biol Chem. 1982 Dec 25;257(24):14830-4.
We describe the isolation and characterization of tryptic peptides of human erythrocyte hypoxanthine-guanine phosphoribosyltransferase. The digest was separated by reverse-phase high pressure liquid chromatography into 30 peaks, 26 of which contained purified peptides. The four complex peaks were resolved by high pressure liquid chromatography with a different reverse-phase column. Each peptide predicted from the recently described amino acid sequence of human erythrocyte hypoxanthine-guanine phosphoribosyltransferase was isolated from this peptide map. Sequence analysis of the purified peptides identified two peptides, 14 and 14d, that differed by an Asn/Asp heterogeneity at the position corresponding to residue 106 of the intact protein. Additional studies indicate that this heterogeneity is due to deamidation of the protein in vivo. This post-translational modification appears to be responsible for some of the electrophoretic heterogeneity observed in the normal erythrocyte enzyme.
我们描述了人红细胞次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶胰蛋白酶肽段的分离与特性鉴定。消化产物通过反相高压液相色谱分离为30个峰，其中26个含有纯化的肽段。这四个复合峰通过使用不同反相柱的高压液相色谱进行解析。从该肽图谱中分离出了根据最近描述的人红细胞次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶氨基酸序列预测的每个肽段。对纯化肽段的序列分析鉴定出两个肽段，即14和14d，它们在与完整蛋白质第106位残基相对应的位置存在Asn/Asp异质性。进一步研究表明，这种异质性是由于蛋白质在体内发生脱酰胺作用所致。这种翻译后修饰似乎是正常红细胞酶中观察到的一些电泳异质性的原因。
