Lee R W, Huttner W B
J Biol Chem. 1983 Sep 25;258(18):11326-34.
The O-sulfation of specific proteins on tyrosine residues was studied using the rat pheochromocytoma cell line PC12 as a model system. In intact PC12 cells labeled with inorganic [35S]sulfate, the major protein substrates for sulfation on tyrosine were four acidic polypeptides with apparent molecular weights of 113,000, 105,000, 86,000, and 84,000 designated as p113, p105, p86, and p84. After labeling of intact PC12 cells with inorganic [32P]phosphate, these four proteins were also found to be phosphorylated at serine residues. Peptide mapping after limited proteolysis indicated sequence homologies between p113 and p105, and between p86 and p84. In lysed PC12 cells, p113, p105, p86, and p84 were phosphorylated at serine residues by an endogenous protein kinase using [32P] ATP. Moreover, in the cell-free preparation, an enzymatic activity was detected that was able to catalyze the sulfation of the four proteins on tyrosine residues. This sulfation reaction, which used adenosine 3'-phosphate 5'-phospho[35S]sulfate as the sulfate donor, occurred in a particulate fraction of PC12 cells and was inhibited by 5 mM EDTA. These results demonstrate the presence in PC12 cells of a novel enzyme, designated here as a tyrosylprotein sulfotransferase, and imply a role for this enzyme in the post-translational processing of specific PC12 cell proteins.
利用大鼠嗜铬细胞瘤细胞系PC12作为模型系统，研究了特定蛋白质酪氨酸残基上的O-硫酸化作用。在用无机[35S]硫酸盐标记的完整PC12细胞中，酪氨酸硫酸化的主要蛋白质底物是四种酸性多肽，其表观分子量分别为113,000、105,000、86,000和84,000，分别命名为p113、p105、p86和p84。在用无机[32P]磷酸盐标记完整PC12细胞后，还发现这四种蛋白质在丝氨酸残基处发生了磷酸化。有限蛋白酶解后的肽图分析表明，p113和p105之间以及p86和p84之间存在序列同源性。在裂解的PC12细胞中，p113、p105、p86和p84利用[32P]ATP在丝氨酸残基处被内源性蛋白激酶磷酸化。此外，在无细胞制剂中，检测到一种能够催化这四种蛋白质酪氨酸残基硫酸化的酶活性。这种硫酸化反应以腺苷3'-磷酸5'-磷酸[35S]硫酸盐作为硫酸盐供体，发生在PC12细胞的微粒部分，并受到5 mM EDTA的抑制。这些结果证明了PC12细胞中存在一种新型酶，在此命名为酪氨酰蛋白磺基转移酶，并暗示该酶在特定PC12细胞蛋白质的翻译后加工中起作用。
