PDF(Pubmed)
Abstract：
CONCLUSIONS: Hydroxy(phenyl)pyruvic acid reductase from Actaea racemosa catalyzes dual reactions in reducing 4-hydroxyphenylpyruvic acid as well as β-hydroxypyruvic acid. It thus qualifies to be part of fukinolic and cimicifugic acid biosynthesis and also photorespiration. The accumulation of fukinolic acid and cimicifugic acids is mainly restricted to Actaea racemosa (Ranunculaceae) and other species of the genus Actaea/Cimicifuga. Cimicifugic and fukinolic acids are composed of a hydroxycinnamic acid part esterified with a benzyltartaric acid moiety. The biosynthesis of the latter is unclear. We isolated cDNA encoding a hydroxy(phenyl)pyruvic acid reductase (GenBank OR393286) from suspension-cultured material of A. racemosa (ArH(P)PR) and expressed it in E. coli for protein production. The heterologously synthesized enzyme had a mass of 36.51 kDa and catalyzed the NAD(P)H-dependent reduction of 4-hydroxyphenylpyruvic acid to 4-hydroxyphenyllactic acid or β-hydroxypyruvic acid to glyceric acid, respectively. The optimal temperature was at 38 °C and the pH optimum at pH 7.5. NADPH is the preferred cosubstrate (Km 23 ± 4 µM). Several substrates are accepted by ArH(P)PR with β-hydroxypyruvic acid (Km 0.26 ± 0.12 mM) followed by 4-hydroxyphenylpyruvic acid (Km 1.13 ± 0.12 mM) as the best ones. Thus, ArH(P)PR has properties of β-hydroxypyruvic acid reductase (involved in photorespiration) as well as hydroxyphenylpyruvic acid reductase (possibly involved in benzyltartaric acid formation).
摘要：
结论：来自Actaea的羟基（苯基）丙酮酸还原酶催化还原4-羟基苯基丙酮酸以及β-羟基丙酮酸的双重反应。因此，它有资格成为fukinolic酸和cimiciffugic酸生物合成以及光呼吸的一部分。呋喃酚酸和cimicfugic酸的积累主要限于总状Actaea（Ranunculaceae）和Actaea/Cimicifuga属的其他物种。拟南芥酸和呋喃酸由被苄基酒石酸部分酯化的羟基肉桂酸部分组成。后者的生物合成尚不清楚。我们从A.racemosa（ArH（P）PR）的悬浮培养材料中分离了编码羟基（苯基）丙酮酸还原酶（GenBankOR393286）的cDNA，并在大肠杆菌中表达以生产蛋白质。异源合成的酶的质量为36.51kDa，并催化NAD（P）H依赖性将4-羟基苯基丙酮酸还原为4-羟基苯基乳酸或β-羟基丙酮酸还原为甘油酸，分别。最佳温度为38°C,最佳pH为pH7.5。NADPH是优选的共底物(Km23±4µM)。ArH（P）PR接受了几种底物，其中β-羟基丙酮酸（Km0.26±0.12mM），然后是4-羟基苯基丙酮酸（Km1.13±0.12mM）是最好的底物。因此，ArH（P）PR具有β-羟基丙酮酸还原酶（参与光呼吸）和羟基苯基丙酮酸还原酶（可能参与苄基酒石酸的形成）的特性。
