Lluis C, Bozal J
Biochim Biophys Acta. 1977 Aug 10;461(2):209-17. doi: 10.1016/0005-2728(77)90171-2.
Chicken liver lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC1.1.1.27) catalyses the reversible reduction reaction of hydroxypyruvate to L-glycerate. It also catalyses the oxidation reaction of the hydrated form of glyoxylate to oxalate and the reduction of the non-hydrated form of glyoxylate to oxalate and the reduction of the non-hydrated form to glycolate. At pH 8, these latter two reactions are coupled. The coupled system equilibrium is attained when the NAD+/NADH ratio is greater than unity. Hydroxypyruvate binds to the enzyme at the same site as the pyruvate. When there are substances with greater affinity to this site in the reaction medium and their concentration is very high, hydroxypyruvate binds to the enzyme at the L-lactate site. In vitro and with purified preparation of lactate dehydrogenase, hydroxypyruvate stimulates the production of oxalate from glyoxylate-hydrated form and from NAD; the effect is due to the fact that hydroxypyruvate prevents the binding of non-hydrated form of glyoxylate to the lactate dehydrogenase in the pyruvate binding site. At pH 8, THE L-glycerate stimulates the production of glycolate from glyoxylate-non-hydrated form and NADH since hydroxypyruvate prevents the binding of glyoxylate-hydrated form to the enzyme
鸡肝乳酸脱氢酶（L-乳酸：NAD⁺氧化还原酶，EC1.1.1.27）催化羟基丙酮酸可逆还原为L-甘油酸的反应。它还催化乙醛酸水合形式氧化为草酸盐以及乙醛酸非水合形式还原为草酸盐，以及乙醛酸非水合形式还原为乙醇酸的反应。在pH 8时，后两个反应是偶联的。当NAD⁺/NADH比值大于1时，达到偶联系统平衡。羟基丙酮酸与丙酮酸在酶的同一部位结合。当反应介质中存在对该部位亲和力更强的物质且其浓度非常高时，羟基丙酮酸在L-乳酸部位与酶结合。在体外，使用纯化的乳酸脱氢酶制剂时，羟基丙酮酸会刺激水合乙醛酸和NAD生成草酸盐；这种作用是由于羟基丙酮酸阻止了非水合乙醛酸在丙酮酸结合部位与乳酸脱氢酶结合。在pH 8时，L-甘油酸会刺激非水合乙醛酸和NADH生成乙醇酸，因为羟基丙酮酸阻止了水合乙醛酸与酶的结合
