Two fundamental physical properties of partially purified trout intestinal alkaline phosphatases which have been examined in detail are thermostability and activation energy. It has been clearly demonstrated that differences in thermostability exist between the trout isozymes, and that as a group they are more thermolabile than mammalian phosphatases. The activation energies of the two main trout phosphatase zones, however, are comparable to mammalian phosphatases. Experiments on cold‐acclimation of hatchery brook trout suggest that a fundamental reorganization of the intestinal alkaline phosphatase complement occurs. There are drastic quantitative differences in the isozyme patterns of 4° C‐acclimated fish and those acclimated to 10° C or 15° C. The 4° isozyme complement has a lower activation energy in the range of 2° C−10° C than does the 10° C isozyme complement. This finding strongly suggests that there is a reconstruction of the phosphatase isozyme complement with cold‐acclimation. This is functionally significant in that it results in the production of enzymes better suited to the new thermal regime. Three mechanisms are discussed as possible regulators of this process.
ASJC Scopus subject areas
- Animal Science and Zoology