3-羟基异丁酸脱氢酶，商业用3-羟基丁酸脱氢酶中的一种杂质。
3-Hydroxyisobutyrate dehydrogenase, an impurity in commercial 3-hydroxybutyrate dehydrogenase.
作者信息
Worrall E B, Gassain S, Cox D J, Sugden M C, Palmer T N
出版信息
Biochem J. 1987 Jan 1;241(1):297-300. doi: 10.1042/bj2410297.
The enzymic determination of D-3-hydroxybutyrate and acetoacetate normally involves the use of 3-hydroxybutyrate dehydrogenase (HBDH, EC 1.1.1.30) of bacterial origin. We show that HBDH from Rhodopseudomonas spheroides (BCL, grade II) contains a 3-hydroxyisobutyrate dehydrogenase (HIBDH) activity: activity with 3-hydroxyisobutyrate as substrate was greater than 10% of that with 3-hydroxybutyrate. However, HBDH could be prepared essentially free of HIBDH activity by incubation at 37 degrees C in the presence of 1 mM-CaCl2, to produce an enzyme preparation that may be used for the specific determination of 3-hydroxybutyrate. Use of the purified enzyme preparations indicated that a major product of valine metabolism in hemidiaphragms from 40 h-starved rats was 3-hydroxyisobutyrate rather than 3-hydroxybutyrate.
D-3-羟基丁酸和乙酰乙酸的酶法测定通常涉及使用源自细菌的3-羟基丁酸脱氢酶（HBDH，EC 1.1.1.30）。我们发现球形红假单胞菌（BCL，二级）的HBDH含有3-羟基异丁酸脱氢酶（HIBDH）活性：以3-羟基异丁酸为底物的活性大于以3-羟基丁酸为底物的活性的10%。然而，通过在1 mM CaCl2存在下于37℃孵育，可制备基本不含HIBDH活性的HBDH，从而得到可用于特异性测定3-羟基丁酸的酶制剂。使用纯化的酶制剂表明，饥饿40小时大鼠半膈肌中缬氨酸代谢的主要产物是3-羟基异丁酸而非3-羟基丁酸。
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