The effect of temperature on enzyme activity and on the affinity of enzymes to their substrates.

The effect of temperature on the activity of several diagnostically important enzymes) was measured. At 30° C, the measured activity of some enzymes already differs from that calculated from the Arrhenius plot, while all the enzymes investigated showed a significant deviation of activity at 37° C. This deviation is independent of the time of pre-incubation (up to 1 hour) and the sample concentration in the assay solution. The activity measured at 25° C after a pre-incubation of 1 hour was independent, of the temperature of pre-incubation up to 40° C. In addition, increased temperature decreased the affinity of 7-glutamyltransferase and leucine arylamidase for their substrates. The theoretical and practical aspects of the findings are discussed.