Brooks S F, Erusalimsky J D, Totty N F, Rozengurt E
Imperial Cancer Research Fund, London, UK.
FEBS Lett. 1990 Jul 30;268(1):291-5. doi: 10.1016/0014-5793(90)81030-r.
The acidic 80 kDa protein kinase C (PKC) substrate was purified from 2.3 x 10(10) Swiss 3T3 fibroblasts. Partial amino acid sequence data were obtained from five peptides generated by S. aureus V8 cleavage of the protein, enabling a total of 91 amino acid residues to be assigned. The sequences of these five peptides were compared to the deduced amino acid sequences of acidic 80-87 kDa PKC substrates from both actively proliferating A431 epidermal carcinoma cells, and fully differentiated neural tissue. Despite their similar physical properties, there was no homology between the peptides derived from the fibroblast 80 kDa protein and the PKC substrate from A431 cells. However, there was 66% homology with the 87 kDa bovine brain protein within the regions covered by the peptides about 30% of the total protein). Furthermore, comparison of the peptides from the fibroblast 80 kDa protein with proteolytic peptides derived from the acidic 80 kDa rat brain protein revealed an overall homology of 89%. These data provide the first direct evidence that the 80 kDa PKC substrate from Swiss 3T3 fibroblasts is closely related to the 80-87 kDa PKC substrates detected in fully differentiated neural tissue.
从2.3×10¹⁰个瑞士3T3成纤维细胞中纯化出酸性80 kDa蛋白激酶C（PKC）底物。通过金黄色葡萄球菌V8蛋白酶对该蛋白进行切割产生了五个肽段，并获得了部分氨基酸序列数据，从而确定了总共91个氨基酸残基。将这五个肽段的序列与来自活跃增殖的A431表皮癌细胞和完全分化的神经组织中的酸性80 - 87 kDa PKC底物的推导氨基酸序列进行了比较。尽管它们具有相似的物理性质，但成纤维细胞80 kDa蛋白衍生的肽段与A431细胞的PKC底物之间没有同源性。然而，在肽段覆盖的区域内，与87 kDa牛脑蛋白有66%的同源性（约占总蛋白的30%）。此外，将成纤维细胞80 kDa蛋白的肽段与来自酸性80 kDa大鼠脑蛋白的蛋白水解肽段进行比较，发现总体同源性为89%。这些数据首次直接证明，瑞士3T3成纤维细胞的80 kDa PKC底物与在完全分化的神经组织中检测到的80 - 87 kDa PKC底物密切相关。
