Pioneer Hi-Bred International, Inc., Plant Breeding Division, Department of Research Specialists, P.O. Box 85, Johnston, Iowa 50131-0085.
Plant Physiol. 1986 May;81(1):41-4. doi: 10.1104/pp.81.1.41.
The metabolism of oleoyl coenzyme A (CoA) was examined in developing seed from two soybean (Glycine max [L.] Merr.) genotypes: Williams, a standard cultivar and A5, a mutant containing nearly twice the oleic acid (18:1) content of Williams. The in vitro rates of esterification of oleoyl-CoA to lysophosphatides by acyl-CoA: lysophosphatidylcholine acyltransferase was similar in both genotypes and lysophosphatidyl-ethanolamine was a poor substrate. Crude extracts desaturated exogenous [1-(14)C]dioleoyl phosphatidylcholine at 14% of the rate achieved with [1-(14)C]oleoyl-CoA, and 50 micromolar lysophosphatidylcholine. The desaturase enzyme also required NADH for full activity. Extracts from Williams contained 1.5-fold more oleoyl phosphatidylcholine desaturase activity, on a fresh weight basis, than did A5 and appeared to have a similar affinity for oleoyl-CoA. There was 1.2- to 1.9-fold more linoleic acid (18:2) in phosphatidylcholine from Williams than from A5, measured at two stages of development, but both genotypes had a similar distribution of fatty acids in the one and two positions. Phosphatidylethanolamine in A5 contained relatively more linoleic acid (18:2) in the one position than did Williams. The increased oleic acid (18:1) content in A5 appeared to be a result of decreased rates of 18:1 desaturation of oleoyl-phosphatidylcholine in this genotype.
对两种大豆（Glycine max [L.] Merr.）基因型（Williams，标准品种和 A5，一种油酸（18:1）含量几乎是 Williams 的两倍的突变体）发育种子中的油酰辅酶 A（CoA）代谢进行了研究。酰基辅酶 A：溶血磷脂酰胆碱酰基转移酶将油酰-CoA 酯化生成溶血磷脂的体外速率在两种基因型中相似，而溶血磷脂-乙醇胺是较差的底物。粗提取物以与 [1-（14）C]油酰-CoA 和 50 微摩尔溶血磷脂相同的速率将外源性[1-（14）C]二油酰磷脂酰胆碱去饱和，而不饱和酶也需要 NADH 才能充分发挥活性。基于鲜重，Williams 中的油酰磷脂酰胆碱去饱和酶活性比 A5 高 1.5 倍，并且似乎对油酰-CoA 具有相似的亲和力。在两个发育阶段，Williams 中的磷脂酰胆碱中的亚油酸（18:2）比 A5 多 1.2-1.9 倍，但两种基因型在一个和两个位置的脂肪酸分布相似。A5 中的磷脂酰乙醇胺在一个位置上的亚油酸（18:2）相对较多。A5 中油酸（18:1）含量的增加似乎是由于该基因型中油酰磷脂酰胆碱 18:1 去饱和率降低所致。
