P450BM-3: absolute configuration of the primary metabolites of palmitic acid.
P450BM-3: absolute configuration of the primary metabolites of palmitic acid.
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P450BM-3：棕榈酸主要代谢物的绝对构型。
DOI：
10.1006/abbi.1999.1156
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发表时间：
1999
影响因子：
3.9
通讯作者：
Peterson,JA
中科院分区：
文献类型：
--
作者：
Truan,G;Komandla,MR;Falck,JR;Peterson,JA
P450BM-3是一种催化自给自足的可溶性细菌P450，在同一多肽上含有一个血红素结构域和一个还原酶结构域。P450BM-3催化氧化短链和长链、饱和和不饱和脂肪酸。在没有和存在脂肪酸底物的情况下，已经确定了血红素结构域的三维结构；然而，底物结合形式的脂肪酸不足以接近血红素铁，从而能够预测氧化的立体选择性。在长链脂肪酸的情况下，产物也可以作为底物进行多次代谢。在本研究中，我们测定了棕榈酸羟化的三个主要产物(15-、14-和13-羟基棕榈酸)的绝对构型。15-羟基和14-羟基是以高度立体选择性的方式产生的(98%R，2%S)，而13-羟基是72%R和28%S的混合物。我们还研究了这三种羟基酸与P450BM-3的结合，发现只有两种羟基(14-羟基和13-羟基棕榈酸)能与P450BM-3结合并被P450BM-3进一步代谢。结果表明，与棕榈油酸结合在氧化酶上的柔韧性不同，棕榈酸在催化循环过程中刚性结合在活性中心。
P450BM-3, a catalytically self-sufficient, soluble bacterial P450, contains on the same polypeptide a heme domain and a reductase domain. P450BM-3 catalyzes the oxidation of short- and long-chain, saturated and unsaturated fatty acids. The three-dimensional structure of the heme domain both in the absence and in the presence of fatty acid substrates has been determined; however, the fatty acid in the substrate-bound form is not adequately close to the heme iron to permit a prediction regarding the stereoselectivity of oxidation. In the case of long-chain fatty acids, the products can also serve as substrate and be metabolized several times. In the current study, we have determined the absolute configuration of the three primary products of palmitic acid hydroxylation (15-, 14-, and 13-OH palmitic acid). While the 15- and 14-hydroxy compounds are produced in a highly stereoselective manner (98% R, 2% S), the 13-hydroxy is a mixture of 72% R and 28% S. We have also examined the binding of these three hydroxy acids to P450BM-3 and shown that only two of them (14-OH and 13-OH palmitic acid) can bind to and be further metabolized by P450BM-3. The results indicate that in contrast to the flexibility of palmitoleic acid bound to the oxidized enzyme, palmitic acid is rigidly bound in the active site during catalytic turnover.