THE TEMPERATURE-COEFFICIENTS OF RIBONUCLEASES FROM TWO SPECIES OF GASTROPOD MOLLUSCS FROM DIFFERENT THERMAL ENVIRONMENTS

¹ The Biological Laboratories, Harvard University, Cambridge 38, Massachussetts

1. Buccinum undatum digestive gland ribonuclease chromatographed on phosphocelulose consists of three enzymatic components, all showing an optimum PH of about pH 5 in acetate buffer. Activation energies of the three components are 21.000, 22,900 and 27,000 cal./mole at pH 5.

2. Fasciolaria tulipa digestive gland ribonuclease chromatographed on phosphocellulose consists of two enzymatic components, both with pH optimm ner pTH5 in acetate buffer. Activation energies of the two components are 19,500 and 24.000 cal./mole at pH 5.

3. It is concluded that the ribonucleases of gastropod digestive glands show little or no adaptation, by way of differences in activation energies, to the thermal environment.