| Abstract: | Effects of heating and urea on the heat-stable alkaline proteinase from white croaker and chum salmon muscle were compared in order to know the regulating mechanism of the proteinase. Chum salmon proteinase required a higher temperature for activity and was more heat-stable than white croaker proteinase. In the presence of 5M urea, the activity was observed to some degree at 37 degrees C only in white croaker proteinase, while both proteinases lost their activities at usual assay temperature around 60 degrees C. These results suggest that the stability of the regulatory and catalytic subunits of the proteinases is somewhat different among fish species. |
