Birckbichler P J, Orr G R, Patterson M K, Conway E, Carter H A, Maxwell M D
Biochim Biophys Acta. 1983 Aug 17;763(1):27-34. doi: 10.1016/0167-4889(83)90021-6.
The low level of transglutaminase activity in virus-transformed human embryonic lung fibroblasts (WI-38 VA13A) increased markedly when cells were exposed to sodium butyrate. The effect of sodium butyrate was time- and concentration-dependent and fully reversible. Transformed cells exposed for 5 days to 1 mM sodium butyrate had fewer cells, showed an 8-10 fold higher transglutaminase activity, and stained more abundantly for transglutaminase and pericellular fibronectin than control cells when examined by indirect immunofluorescence. Non-transformed cells (WI-38) showed only a 2-4-fold increase in transglutaminase activity when treated in a similar manner. Studies with metabolic inhibitors revealed the increase in activity was the result of synthesis of new protein. Kinetic studies showed the affinity of putrescine for the enzyme was essentially unchanged but the number of active sites increased 9-fold following exposure to sodium butyrate. Enhanced transglutaminase activity returned to control levels within 7 days after subculture and sodium butyrate removal. These findings suggest that sodium butyrate offers a potential model system to understand better the role of transglutaminase in cells in culture; particularly growth control in transformed cells.
当病毒转化的人胚肺成纤维细胞（WI - 38 VA13A）暴露于丁酸钠时，其转谷氨酰胺酶活性的低水平显著增加。丁酸钠的作用具有时间和浓度依赖性，且完全可逆。通过间接免疫荧光检查时，暴露于1 mM丁酸钠5天的转化细胞数量减少，转谷氨酰胺酶活性高出8 - 10倍，且转谷氨酰胺酶和细胞周围纤连蛋白的染色比对照细胞更丰富。以类似方式处理时，未转化细胞（WI - 38）的转谷氨酰胺酶活性仅增加2 - 4倍。用代谢抑制剂进行的研究表明，活性增加是新蛋白质合成的结果。动力学研究表明，腐胺对该酶的亲和力基本未变，但暴露于丁酸钠后活性位点数量增加了9倍。传代培养并去除丁酸钠后，增强的转谷氨酰胺酶活性在7天内恢复到对照水平。这些发现表明，丁酸钠提供了一个潜在的模型系统，以更好地理解转谷氨酰胺酶在培养细胞中的作用；特别是在转化细胞中的生长控制作用。
