Positional specificities of acyl coenzyme A: glycerophosphate and acyl coenzyme A: monoacylglycerophosphate acyltransferases in Escherichia coli.
Positional specificities of acyl coenzyme A: glycerophosphate and acyl coenzyme A: monoacylglycerophosphate acyltransferases in Escherichia coli.
复制标题
大肠杆菌中酰基辅酶 A：甘油磷酸酯和酰基辅酶 A：单酰基甘油磷酸酯酰基转移酶的位置特异性。
DOI：
10.1016/s0021-9258(19)43689-2
复制
发表时间：
1973
期刊：
影响因子：
--
通讯作者：
S. Wakil
中科院分区：
文献类型：
--
作者：
H. Okuyama;S. Wakil
从大肠杆菌B中分离的颗粒制剂催化1-酰基-sn-甘油3-磷酸（1-酰基-GP）与油酰-CoA和棕榈酰-CoA的酰化。确定了酰基-CoA：1-酰基-GP酰基转移酶的最佳反应条件。该酰基转移酶对1-酰基-GP具有特异性，并且在所用条件下不酰化2-酰基-sn-甘油3-磷酸（2-酰基-GP）。当棕榈酰辅酶A是底物时，产生单酰基-sn-甘油3-磷酸（单酰基-GP）和二酰基-sn-甘油3-磷酸（二酰基-GP）。这两种产品表现出典型的供应商-产品关系。当使用油酰-CoA时，主要产物是二酰基-GP;形成单酰基-GP，但在孵育2分钟内其量达到非常低的稳态水平。甘油磷酸与不饱和或饱和酰基-CoA短时间孵育后形成的单酰基-GP的结构分析显示主要异构体是1-酰基-GP。形成的2-酰基-GP的量相对较小。在甘油磷酸的酰化反应中，2-酰基-GP的积累不足不是由于2-酰基-GP异构化为1-酰基-GP异构体，在放射性甘油磷酸与不饱和酰基-CoA的酰化反应中，加入未标记的1-酰基-GP可以有效地捕获放射性单酰基-GP，而加入未标记的2-酰基-GP则不能有效地捕获。在1-酰基-GP或2-酰基-GP存在下捕获的单酰基-GP主要是1-酰基-GP异构体。大肠杆菌主要通过1-酰基-GP作为中间体，而不管底物是饱和还是不饱和酰基-CoA。
A particulate preparation isolated fromEscherichia coliB catalyzes the acylation of 1-acyl-sn-glycerol 3-phosphate (1-acyl-GP) with both oleoyl-CoA and palmitoyl-CoA. The optimum conditions were determined for the acyl-CoA: 1-acyl-GP acyltransferase. The acyltransferase is specific for the 1-acyl-GP and does not acylate 2-acyl-sn-glycerol 3-phosphate (2-acyl-GP) under the conditions used.The particulate preparation also catalyses the acylation ofsn-glycerol 3-phosphate (glycerophosphate) with both palmitoyl-CoA and oleoyl-CoA. When palmitoyl-CoA is the substrate, both monoacyl-sn-glycerol 3-phosphate (monoacyl-GP) and diacyl-sn-glycerol 3-phosphate (diacyl-GP) are produced. The two products show a typical precursor-product relationship. When oleoyl-CoA is used, the major product is diacyl-GP; monoacyl-GP is formed, but the amount reaches a very low steady state level within 2 min of incubation.Structural analyses of the monoacyl-GP formed after short time incubations of glycerophosphate with unsaturated or saturated acyl-CoAs showed the major isomer to be 1-acyl-GP. The amounts of 2-acyl-GP formed are relatively small. The lack of accumulation of 2-acyl-GP during the acylation of glycerophosphate is not due to the isomerization of 2-acyl-GP to the 1-acyl-GP isomer.During the acylation of radioactive glycerophosphate with unsaturated acyl-CoA, radioactive monoacyl-GP is trapped effectively by the addition of nonlabeled 1-acyl-GP but ineffectively by adding nonlabeled 2-acyl-GP. The monoacyl-GP trapped in the presence of either 1-acyl-GP or 2-acyl-GP is mostly the 1-acyl-GP isomer.Thus, the pathway of diacyl-GP synthesis from glycerophosphate inE. coliis primarily via the 1-acyl-GP as intermediate regardless of whether the substrate is saturated or unsaturated acyl-CoA.