Cooper C L, Lueking D R
J Lipid Res. 1984 Nov;25(11):1222-32.
The membrane localization and properties of the Rhodopseudomonas sphaeroides sn-glycerol-3-phosphate acyltransferase have been examined utilizing enzymatically prepared acyl-acyl carrier protein (acyl-ACP) substrates as acyl donors for sn-glycerol-3-phosphate acylation. Studies conducted with membranes prepared from chemotrophically and phototrophically grown cells show that sn-glycerol-3-phosphate acyltransferase activity is predominantly (greater than 80%) associated with the cell's cytoplasmic membrane. Enzyme activity associated with the intracytoplasmic membranes present in phototrophically grown R. sphaeroides was within the range attributable to cytoplasmic membrane contamination of this membrane fraction. Enzyme activity was optimal at 40 degrees C and pH 7.0 to 7.5, and required the presence of magnesium. No enzyme activity was observed with any of the long-chain acyl-CoA substrates examined. Vaccenoyl-ACP was the preferred acyl-ACP substrate and vaccenoyl-ACP and palmitoyl-ACP were independently utilized to produce lysophosphatidic and phosphatidic acids. With either vaccenoyl-ACP or palmitoyl-ACP as sole acyl donor substrate, the lysophosphatidic acid formed was primarily 1-acylglycerol-3-phosphate and the Km(app) for sn-glycerol-3-phosphate utilization was 96 microM. The implications of these results to the mode and regulation of phospholipid synthesis in R. sphaeroides are discussed.
利用酶促制备的酰基 - 酰基载体蛋白（acyl - ACP）底物作为sn - 甘油 - 3 - 磷酸酰化的酰基供体，研究了球形红假单胞菌sn - 甘油 - 3 - 磷酸酰基转移酶的膜定位和性质。对由化能营养生长和光合营养生长的细胞制备的膜进行的研究表明，sn - 甘油 - 3 - 磷酸酰基转移酶活性主要（大于80%）与细胞的细胞质膜相关。与光合营养生长的球形红假单胞菌中存在的胞内膜相关的酶活性，处于该膜部分细胞质膜污染所致的范围内。酶活性在40℃和pH 7.0至7.5时最佳，并且需要镁的存在。在所检测的任何长链酰基辅酶A底物中均未观察到酶活性。十八碳烯酰 - ACP是首选的酰基 - ACP底物，并且十八碳烯酰 - ACP和棕榈酰 - ACP可独立用于产生溶血磷脂酸和磷脂酸。以十八碳烯酰 - ACP或棕榈酰 - ACP作为唯一的酰基供体底物时，形成的溶血磷脂酸主要是1 - 酰基甘油 - 3 - 磷酸，并且sn - 甘油 - 3 - 磷酸利用的Km(app)为96μM。讨论了这些结果对球形红假单胞菌中磷脂合成模式和调节的影响。
