Coleman R A, Bell R M
J Biol Chem. 1980 Aug 25;255(16):7681-7.
Enzyme activities of the sn-glycerol 3-phosphate (glycerol-P) and of the dihydroxyacetone-phosphte (DHAP) pathway of glycerolipid biosynthesis were investigated during the differentiation of 3T3-L1 preadipocytes into adipocytes. Total particulate glycerol-P and DHAP acyltransferase activities increased 70- and 30-fold, respectively, during differentiation induced with methylisobutylxanthine and dexamethasone. The N-ethylmaleimide-sensitive (microsomal) glycerol-P and DHAP acyltransferase activities were virtually undetectable in nondifferentiated cells, and increased in parallel over 70-fold during differentiation. These and several kinetic observations are consistent with the induction of a single microsomal enzyme having dual activity. During differentiaion, the N-ethylmaleimide-resistant DHAP acyltransferase activity increased 10-fold, suggesting the presence of at least two DHAP acyltransferase isoenzymes. Qualitatively similar changes in microsomal glycerol-P and DHAP acyltransferase activities were observed when cell differentiation was induced with insulin or with insulin plus dexamethasone and methylisobutylxanthine. Acyl-DHAP oxidoreductase (EC 1.1.1.101) specific activity increased only 3- to 5-fold during adipocyte differentiation. Alkyl-DHAP synthase activity was not detected. These data demonstrate that selective changes in enzyme activities of the gycerol-P pathways of glycerolipid synthesis occur during the differentiation of 3T3-L1 preadipocytes.
在3T3-L1前脂肪细胞分化为脂肪细胞的过程中，研究了甘油磷脂生物合成的sn-甘油-3-磷酸（甘油-P）和二羟基丙酮磷酸（DHAP）途径的酶活性。在用甲基异丁基黄嘌呤和地塞米松诱导分化期间，总颗粒甘油-P和DHAP酰基转移酶活性分别增加了70倍和30倍。N-乙基马来酰亚胺敏感的（微粒体）甘油-P和DHAP酰基转移酶活性在未分化细胞中几乎检测不到，在分化过程中平行增加超过70倍。这些以及一些动力学观察结果与诱导具有双重活性的单一微粒体酶一致。在分化过程中，N-乙基马来酰亚胺抗性的DHAP酰基转移酶活性增加了10倍，表明至少存在两种DHAP酰基转移酶同工酶。当用胰岛素或胰岛素加地塞米松和甲基异丁基黄嘌呤诱导细胞分化时，观察到微粒体甘油-P和DHAP酰基转移酶活性有定性相似的变化。酰基-DHAP氧化还原酶（EC 1.1.1.101）的比活性在脂肪细胞分化过程中仅增加3至5倍。未检测到烷基-DHAP合酶活性。这些数据表明，在3T3-L1前脂肪细胞分化过程中，甘油磷脂合成的甘油-P途径的酶活性发生了选择性变化。
