AN ALTERNATIVE TO ALLOSTERISM AND COOPERATIVITY IN INTERPRETATION OF ENZYME KINETIC DATA
AN ALTERNATIVE TO ALLOSTERISM AND COOPERATIVITY IN INTERPRETATION OF ENZYME KINETIC DATA
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DOI：
10.1021/bi00842a008
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发表时间：
1968-01-01
期刊：
影响因子：
2.9
通讯作者：
FISHER, JR
中科院分区：
文献类型：
--
作者：
SWEENY, JR;FISHER, JR
几种合作模型被用来解释调节酶观察到的速度和底物浓度之间的S型关系，例如亚基之间的变构相互作用和多结合位点模型。即使合作模型可以解释Sigmoid数据，协作性也不是必不可少的。需要单一的、独立的活性部位和占据结合部位的多个反应路径的模型也可以解释S型数据。S型数据似乎只能消除有序序列模型(即那些只有一条反应路径的模型)，这些模型只涉及每个底物的一个分子与一个酶分子的结合。任何符合1/V=[α]+b[S]F形式的速率方程的模型，其中x等于或小于[长划线]2，则速度与底物浓度之间呈S型关系。提出了一组15个可归结为上述形式方程的稳态模型。这些模型不需要协作性，也不需要在给定时间将超过1个底物分子结合到每个催化位置以显示Sigmoid。
Several kinds of cooperative models were used to explain sigmoid relationships between velocities and substrate concentrations observed with regulatory enzymes, e.g., allosteric interactions between subunits and multiple binding site models. Even though cooperative models can explain sigmoid data, cooperativity is not essential. Models requiring single, independent active sites with multiple reaction pathways by which the binding sites are occupied can also explain sigmoid data. It appears that sigmoid data can only eliminate ordered sequence models (i.e., those with a single reaction pathway) which involve the binding of only 1 molecule of each substrate to 1 molecule of enzyme. Any model that conforms to a rate equation of the form, 1/V = [alpha] + b[S]F, where x is equal to or less than[long dash]2, will give a sigmoid relationship between velocity and substrate concentration. A group of 15 steady-state models which can reduce to equations of the above form axe presented. These models do not require cooperativity or the binding of more than 1 molecule of substrate to each catalytic site at a given time in order to exhibit sigmoidness.