Schneider P B
Biochim Biophys Acta. 1975 Jul 27;397(1):110-6. doi: 10.1016/0005-2744(75)90184-9.
The crystallization of bovine glycerol kinase (ATP:glycerol 3-phosphotransferase EC 2.7.1.30) is reported along with a study on the unusual activation of this enzyme by ethanol. The enzyme was extracted from calf lever andusual activation of this enzyme by ethanol. The enzyme was extracted from calf liver and purified 5900-fold giving crystals with a 5% yield. The kinetics of the enzyme with regard to glycerol and ATP were studied by varying the concentration of one substrate while keeping the other at saturating levels, and the effect of ethanol was observed by adding it at levels of 5% (v/v). Ethanol increased the V in both cases almost 2-fold. The apparent Km of ATP was 3.5 - 10(-6) and was increased to 7.6 - 10(-6) in the presence of ethanol. The apparent Km for glycerol was 3 - 10(-5) and was increased to 12 - 10(-5) when ethanol was added. A number of other alcohols had a similar activating effect except for 1,2-diols which only inhibited the enzyme. These findings are consistent with the explanation that alcohols compete with glycerol (hence also with the glycerophosphate product) for a hydroxy binding site on the enzyme. This leads to more rapid dissociation of the glycerophosphate (i.e. an increase in the steady-state constant, "k+2" resulting in an increased V).
报道了牛甘油激酶（ATP：甘油3 - 磷酸转移酶，EC 2.7.1.30）的结晶过程以及对该酶受乙醇异常激活的研究。该酶从小牛肝脏中提取，并经过5900倍纯化，结晶产率为5%。通过改变一种底物的浓度同时保持另一种底物处于饱和水平，研究了该酶对甘油和ATP的动力学，并且通过添加5%（v/v）的乙醇观察其效果。在两种情况下，乙醇都使V值增加了近2倍。ATP的表观Km值为3.5×10⁻⁶，在乙醇存在下增加到7.6×10⁻⁶。甘油的表观Km值为3×10⁻⁵，添加乙醇后增加到12×10⁻⁵。除了1,2 - 二醇仅抑制该酶外，许多其他醇类具有类似的激活作用。这些发现与以下解释一致：醇类与甘油（因此也与甘油磷酸产物）竞争酶上的羟基结合位点。这导致甘油磷酸更快解离（即稳态常数“k+2”增加，从而导致V增加）。
