Cooper J A, Esch F S, Taylor S S, Hunter T
J Biol Chem. 1984 Jun 25;259(12):7835-41.
Enolase, lactate dehydrogenase, and phosphoglycerate mutase have previously been found to contain phosphotyrosine in fibroblasts transformed by Rous sarcoma virus, which encodes a tyrosine-specific protein kinase. However, these phosphorylations are not stoichiometric, and their significance for any aspect of the transformed phenotype is unknown. We show here that enolase and lactate dehydrogenase are each phosphorylated chiefly at a single tyrosine in Rous sarcoma virus-transformed cells. The purified enzymes can also be phosphorylated at the same tyrosine in vitro when incubated with an immunoprecipitated retroviral transforming protein having associated tyrosine protein kinase activity. The phosphorylated tyrosine in lactate dehydrogenase is amino acid 238. The phosphorylated tyrosine in enolase lies in a sequence homologous to that surrounding histidine 43 in yeast enolase. Although the phosphorylated sequence in lactate dehydrogenase shows some homology to those sequences surrounding phosphotyrosines found in retroviral transforming proteins, the phosphorylated sequence in enolase is quite different.
烯醇化酶、乳酸脱氢酶和磷酸甘油酸变位酶先前已被发现在经劳氏肉瘤病毒转化的成纤维细胞中含有磷酸酪氨酸，该病毒编码一种酪氨酸特异性蛋白激酶。然而，这些磷酸化反应并非化学计量的，并且它们对转化表型的任何方面的意义尚不清楚。我们在此表明，在劳氏肉瘤病毒转化的细胞中，烯醇化酶和乳酸脱氢酶各自主要在单个酪氨酸位点被磷酸化。当与具有相关酪氨酸蛋白激酶活性的免疫沉淀逆转录病毒转化蛋白一起孵育时，纯化的酶在体外也能在相同的酪氨酸位点被磷酸化。乳酸脱氢酶中被磷酸化的酪氨酸是第238位氨基酸。烯醇化酶中被磷酸化的酪氨酸位于与酵母烯醇化酶中组氨酸43周围序列同源的序列中。虽然乳酸脱氢酶中的磷酸化序列与在逆转录病毒转化蛋白中发现的磷酸酪氨酸周围的那些序列有一些同源性，但烯醇化酶中的磷酸化序列却大不相同。
