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本文在纯化小鼠肾脏芳香酰胺酶(E.C.3.4.11.2.Arylamidase,简称AAD)的基础上,进一步作了动力学方面的研究。此酶对热较为稳定;对尿素失活敏感。在Co~(++)存在下,此酶的Km和Vm均变大,但Lineweaver-Burk作图中其斜率不变,属反竞争性类型。苯丙氨酸(Phe)、甲硫氨酸(Met)和亮氨酸(Leu)是此酶的竞争性抑制剂,其Ki值分别为0.3×10~(-3)M、0.5×10~(-3)M和3.7×10~(-3)M。此酶还对L-亮氨酰胺有轻微的水解作用,其Km值为2.4 x 10~(-3)M。此外,抑制性氨基酸能拮抗Co~(++)对酶的激活作用,但二者似乎作用于酶的不同部位。
Based on the purification of the mouse kidney amidase (E.C.3.4.11.2.Arylamidase, AAD for short), further kinetic studies have been made. This enzyme is relatively stable to heat; sensitive to urea inactivation. In the presence of Co ~ (++), the Km and Vm of the enzyme become larger, but Lineweaver-Burk plot of its slope unchanged, is an anti-competitive type. Phe, Met and Leu are competitive inhibitors of this enzyme with Ki values of 0.3 × 10 -3 M, 0.5 × 10 -3 M, (-3) M and 3.7 × 10 ~ (-3) M. This enzyme also has a slight hydrolysis of L-leucinamide with a Km of 2.4 x 10 ~ (-3) M. In addition, inhibitory amino acids can antagonize Co ~ (++) on the enzyme activation, but both seem to act on different parts of the enzyme.