Wali A S, Mattoo A K, Modi V V
Int J Pept Protein Res. 1979 Aug;14(2):99-106. doi: 10.1111/j.1399-3011.1979.tb01732.x.
Temperature-activity and temperature-stability relationships of malate dehydrogenases from eight thermophilic fungi were determined. Temperature optima for maximum activity of the enzymes varied between 50 degrees and 60 degrees and the Arrhenius plots were linear between 5 degrees and 50 degrees. The energies of activation ranged from 2.1 Kcal/mol for the enzyme from Sporotrichum thermophile to 9.1 Kcal/mol for that from Penicillium duponti. Heat inactivation kinetics at 50 degrees revealed heat lability of the enzyme from most of the thermophilic fungi. The t1/2's (min) were less than 10 for the enzymes from P. duponti, S. thermophile and Thermoascus aurantiacus; less than 30 for those from Chaetomium thermophile var. coprophile, H. lanuginosa and C. thermophile var. dissitum; and greater than 30 for those from Mucor pusillus and H. insolens. Salts of Na+, K+ and NH4+, and citrate protected the enzymes from H. lanuginosa, C. thermophile var. dissitum and M. pusillus against heat inactivation.
测定了来自8种嗜热真菌的苹果酸脱氢酶的温度-活性和温度-稳定性关系。这些酶最大活性的最适温度在50℃至60℃之间变化，并且在5℃至50℃之间阿累尼乌斯曲线呈线性。活化能范围从嗜热枝孢霉的酶的2.1千卡/摩尔到杜邦青霉的酶的9.1千卡/摩尔。50℃下的热失活动力学表明大多数嗜热真菌的酶对热不稳定。杜邦青霉、嗜热枝孢霉和橘黄嗜热毁丝霉的酶的t1/2（分钟）小于10；嗜热毛壳粪生变种、绒毛栓菌和嗜热毛壳不同变种的酶的t1/2小于30；微小毛霉和不溶性栓菌的酶的t1/2大于30。Na+、K+和NH4+的盐以及柠檬酸盐可保护绒毛栓菌、嗜热毛壳不同变种和微小毛霉的酶免受热失活。
