Enzymes screening experiments

Table IV. Mean Irradiation Flavor Intensity Scores of Enzyme-Inactivated Beefsteaks after Irradiation at 6.0 Megarads in Initial Process Variable Screening Experiment...

Literature data of optimum temperatures of enzymes has often been determined by studying one variable at a time. As Interaction effects between other variables and the reaction temperature are to be expected, the concept of optimum temperature is dubious. With enzymes from warm-blooded animals, a reaction temperature close to the normal body temperature of the animal, will probably be a good approximation in a screening experiment. For a detailed optimization the temperature variation must be considered. 

In most cases, it is best to employ a temperature near or below the catalyst s thermostable limit (determined from the technical hterature, the manufacturer, or through screening experiments). However, in a few cases, low temperature operahon is desired. One example is acyl transfer reachons involving pephde. A common problem associated with this category is the occurrence of a side reachon, hydrolysis. Moreover, a compehhon exists between the amino acid acyl acceptor and water, both acting as nucleophiles toward the acyl-enzyme intermediate. Adlercreutz and co-workers discovered that the selectivity of chymotrypsin toward acyl exchange over hydrolysis increased as temperature decreased. - Hence, operation is best at lower temperatures. A second situation is when low temperature selectively precipitates the desired product (discussed below). 

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