Selective changes in microsomal enzymes of triacylglycerol phosphatidylcholine, and phosphatidylethanolamine biosynthesis during differentiation of 3T3-L1 preadipocytes.
Selective changes in microsomal enzymes of triacylglycerol phosphatidylcholine, and phosphatidylethanolamine biosynthesis during differentiation of 3T3-L1 preadipocytes.
复制标题
DOI：
--
复制
发表时间：
1978-10
期刊：
影响因子：
--
通讯作者：
Rosalind A. Coleman;B. C. Reed;J. Mackall;A. K. Student;M. Lane;R. Bell
中科院分区：
文献类型：
--
作者：
Rosalind A. Coleman;B. C. Reed;J. Mackall;A. K. Student;M. Lane;R. Bell
3T3-LL前脂肪细胞融合后分化为具有脂肪细胞形态和生化特征的细胞。以前的工作表明，在脂肪转化过程中，参与脂肪酸生物合成的几种酶显著增加。通过在生物素缺乏的培养液中培养脂肪细胞，研究了脂肪细胞形态发育过程中促进去新脂肪酸生物合成的必要性。当去新脂肪酸的生物合成被抑制94%以上时，脂肪转化的开始时间和程度都不受影响，[14C]棕榈酸酯在三酰甘油中的掺入也不受影响。因此，去努乌脂肪酸的生物合成不是脂肪转化所必需的。在分化和未分化的3T3-LL细胞和脂肪转化频率较低的克隆3T3-C2细胞的颗粒组分中，研究了三酰甘油、磷脂酰胆碱和磷脂酰乙醇胺生物合成的微粒体酶活性。在3T3-LL细胞脂肪分化过程中，脂肪辅酶A连接酶(EC 6.2.1.3)、甘油-3-β酰基转移酶(EC 3.1.3.9)、溶血磷脂酸酰基转移酶(EC 2.3.1.20)和甘油二酯酰基转移酶(EC 2.3.1.20)四种微粒体酶的表达同时协同增加。这些酶的比活力是未分化的3T3-LL或对照3T3-C2细胞的30~100倍。IV-乙基马来酰亚胺抑制研究表明，甘油3-β酰基转移酶的增加几乎完全是微粒体的。分化的3T3-LL细胞和对照3T3-C2细胞的细胞总磷脂酸性磷酸酶(EC 3.1.3.4)活性相同。二酰甘油胆碱(EC 2.7.8.2)和乙醇胺磷酸转移酶(EC 2.7.8.1)在分化3T3-LL细胞中的特异性活性
3T3-Ll preadipocytes differentiate after reaching confluence into cells having morphological and biochemical characteristics of adipocytes. Previous work has shown that several enzymes involved in fatty acid biosynthesis increase dramatically during the adipose conversion. The necessity for enhanced de nouo fatty acid biosynthesis in the development of the adipocyte morphology was investigated by growing the cells in biotin-deficient medium. When de nouo fatty acid biosynthesis was inhibited more than 94%, neither the time of onset nor the extent of adipose conversion was affected, and the incorporation of [14C]palmitate into triacylglycerol was unimpaired. Thus, de nouo fatty acid biosynthesis is not essential for adipose conversion. The microsomal enzyme activities of triacylglycerol, phosphatidylcholine, and phosphatidylethanolamine biosynthesis were investigated in particulate fractions derived from differentiated and nondifferentiated 3T3-Ll cells, and from 3T3-C2 cells, a clone having a low frequency of adipose conversion. During adipocyte differentiation of 3T3-Ll cells, there was a simultaneous and coordinated increase in four of the microsomal enzymes of triacylglycerol biosynthesis: fatty acid CoA ligase (EC 6.2.1.3), glycerol-3-P acyltransferase (EC 3.1.3.9), lysophosphatidic acid acyltransferase and diacylglycerol acyltransferase (EC 2.3.1.20). The specific activities of these enzymes were 30to loo-fold greater than those in undifferentiated 3T3-Ll or control 3T3-C2 cells. IV-Ethylmaleimide inhibition studies indicated that the increase in glycerol3-P acyltransferase was almost entirely microsomal. Total cellular phosphatidic acid phosphatase (EC 3.1.3.4) activity was identical in differentiated 3T3-Ll and control 3T3-C2 cells. Diacylglycerol choline (EC 2.7.8.2) and ethanolamine phosphotransferase (EC 2.7.8.1) specific activities in differentiating 3T3-Ll cells