Protein enzymes play an important role in many physiological processes, such as growth and reproduction. The addition of phosphates activates many proteins, and enzymes called phosphatases remove these phosphates when the activated protein has finished its work. Phosphatases operate best at their optimal temperature.
Both acid and alkaline phosphatases exist in living tissues. Alkaline phosphatase works best when the pH is about 8.6. An acid pH (below 7.0) hampers the activity of alkaline phosphatase, and a pH below 5.0 might denature it, according to the Journal of Bacteriology.
In the human body, the optimum temperature of alkaline phosphatase does not range far from 37 degrees Celsius, the normal body temperature. For example, the optimum temperature of alkaline phosphatase taken from a mole caused by tapeworm cysts proved to be 40 degrees Celsius, according to the Pakistan Journal of Medical Sciences.
Variant Optimum Temperatures
Different types of alkaline phosphatase have different optimum temperatures. It is about 42 degrees Celsius in the intestines of lizards, according to Paul Licht, and 37 degrees Celsius in the bacterium Bordetella bronchiseptica, according to the Canadian Journal of Comparative Medicine. The optimal temperature may differ when taken from the cell to which it belongs. Alkaline phosphate has an optimum temperature of 40 degrees Celsius in the cells of the fungus Cenococcus grandiforme. But when the same enzyme was removed from the cell and purified, its optimum temperature was 30 degrees Celsius, according to Applied and Environmental Microbiology.
- "Biology"; Neil A. Campbell, Jane B. Reece and Lawrence G. Mitchell; 1999
- Pakistan Journal of Medical Sciences: Study of Alkaline Phosphatase from Human Hydatidiform Mole
- Deep Blue at the University of Michigan: The Temperature Dependence of...