Nitisewojo P, Hultin H O
Eur J Biochem. 1976 Aug 1;67(1):87-94. doi: 10.1111/j.1432-1033.1976.tb10636.x.
A comparison was made of some kinetic properties of three chicken lactate dehydrogenase isoenzymes (1, 3 and 5) at 4, 16, 23 and 40 degrees C. Assays were performed with an enzyme concentration of 0.01 muM at pH 6.0. Under the conditions of assay, lactate dehydrogenase 3 and 5 bound to the particulate fraction of homogenized skeletal muscle and were evaluated in the soluble and particulate state. Binding of isoenzymes 3 and5 to the cellular particulate fraction decreased V. This decrease was much greater for lactate dehydrogenase 5 and 3. Values of V for lactate dehydrogenase isoenzymes 1 and 3 did not follow a simple Arrhenius relationship; there was a rapid change in activity between 16 and 23 degrees C. The apparent Km (pyruvate) values of all isoenzymes (bound or soluble) increased with increasing temperature, changing 4--10-fold. The apparent Km for lactate dehydrogenase 5 was greater than that for lactate dehydrogenase 3, which in turn was greater than that for lactate dehydrogenase 1.
对三种鸡乳酸脱氢酶同工酶（1、3和5）在4、16、23和40摄氏度下的一些动力学特性进行了比较。在pH 6.0条件下，以0.01μM的酶浓度进行测定。在测定条件下，乳酸脱氢酶3和5与匀浆骨骼肌的颗粒部分结合，并在可溶性和颗粒状态下进行评估。同工酶3和5与细胞颗粒部分的结合降低了V。乳酸脱氢酶5和3的这种降低幅度更大。乳酸脱氢酶同工酶1和3的V值不遵循简单的阿伦尼乌斯关系；在16至23摄氏度之间活性有快速变化。所有同工酶（结合型或可溶性）的表观Km（丙酮酸）值随温度升高而增加，变化4至10倍。乳酸脱氢酶5的表观Km大于乳酸脱氢酶3的，而乳酸脱氢酶3的又大于乳酸脱氢酶1的。
