Properties of muscle glyceraldehyde-3-phosphate dehydrogenase from the cold-adapted antarctic fish Dissostichus mawsoni

Abstract

1. 1. Muscle glyceraldehyde-3-phosphate dehydrogenase ( d-glyceraldehyde 3-phosphate:NAD oxidoreductase (phosphorylating), EC 1.2.1.12) from the Antarctic cold-adapted fish Dissostichus mawsoni has been examined for evidence of cold adaptation at the molecular level. It has been found to be very similar to the rabbit muscle enzyme with regard to molecular size, amino acid composition, electrophoretic properties and pH-activity profile. Similarity in the respective binding environments for the substrate glyceraldehyde 3-phosphate is suggested by similarity of the K m values, susceptibility to substrate inhibition, reactivity with the specific acylating agent β-(2-furyl) acryloyl phosphate, and the effects of temperature on these characteristics. 2. 2. There were large differences in the utilization of NAD + and its analogues. K m values observed for the D. mawsoni enzyme with NAD +, thio-NAD +, 3-acetylpyridine adenine dinucleotide, and 3-acetylpyridine hypoxanthine nucleotide average about 5-fold greater than the corresponding values for the rabbit enzyme. 3. 3. The activation energy of the glyceraldehyde 3-phosphate oxidation-NAD + reduction reaction as catalyzed by the D. mawsoni enzyme is 14 500 ± 1700 cal/mole , which is lower than the 18 100 ± 1200 cal/mole characteristic of the reaction catalyzed by the rabbit enzyme. The D. mawsoni has a higher specific activity near 0° than the rabbit enzyme. The D. mawsoni enzyme also was neither inactivated nor dissociated by ATP or AMP at low temperature, while the rabbit enzyme was inactivated and dissociated under the same conditions.