Fig. 8. Effect of preincubation temperature (15 min) on the activity of branchial CA isoforms of C. hamatus, T. bernacchii and A. anguilla measured by the electrometric method at 0°C. Values are means ± S.E.M. of 3 experiments. For details, see Materials and methods. The dashed lines indicate the temperatures above which the activity of each isoform is markedly reduced.