Ottaway J H, Apps D K
Biochem J. 1972 Dec;130(3):861-70. doi: 10.1042/bj1300861.
The use of computer-based isotach plots, relating reaction velocity to simultaneous variation of two substrates or effectors of an enzyme, in producing estimates of the parameters of enzyme rate equations was investigated. The computer program (;SYMAP') incorporates an interpolation algorithm, and the superiority of this over visual estimation in producing interpolated velocity values for the estimation of parameter values by conventional double-reciprocal plots is described. The usefulness of the SYMAP program in monitoring the process of fitting data obtained by simultaneous changes in two experimental variables is also described. It is shown that if the residual errors are weighted by a procedure described elsewhere (Ottaway, 1971b, 1973), the percentage error of the computed velocity is distributed evenly over a plot which contains a 100-fold variation in the concentration of one substrate and a 500-fold variation in the concentration of Mg(2+), and in which the velocity of the reaction (that catalysed by NAD kinase) varies over a 60-fold range. The two-dimensional percentage error plot was used to assess the limits within which an incomplete inhibition equation is valid, and to detect a discrepancy in an expected good fit, caused by an impurity in one of the substrates.
研究了使用基于计算机的等速线图，将反应速度与酶的两种底物或效应物的同时变化相关联，以估算酶速率方程的参数。计算机程序（SYMAP）包含一种插值算法，并描述了其相对于视觉估计在通过传统双倒数图估算参数值时生成插值速度值方面的优越性。还描述了SYMAP程序在监测由两个实验变量同时变化获得的数据拟合过程中的有用性。结果表明，如果按照其他地方描述的程序（奥塔韦，1971b，1973）对残差进行加权，计算速度的百分比误差会均匀分布在一个图上，该图中一种底物的浓度有100倍的变化，Mg(2+)的浓度有500倍的变化，并且反应（由NAD激酶催化）的速度在60倍的范围内变化。二维百分比误差图用于评估不完全抑制方程有效的范围，并检测由一种底物中的杂质导致的预期良好拟合中的差异。
