| Popis: |
1. 1. The primitive snake Boa constrictor presents in the stripped hemolysate one component which from O2, equilibrium curves produced the following values: log P50 ± −0.1 and Hill coefficient nH = 1.1, independent of pH. 2. 2. Bothrops alternatus, an evolved snake, presents two components in the hemolysate with functional parameters: log P50 = 0.4 and nH = 1.7 at pH 7.1, decreasing to log P50 = −0.1 and nH ± 1.4 at pH 8.2. 3. 3. In the presence of ATP, an increase to log P50 ± 0.9 and nH ± 2 is found in both snake hemolysates, up to pH 7.8 4. 4. Molecular weight determinations by gel filtration at pH 8 show only the dimeric form (mol. wt 32,000) in B. constrictor hemolysate, and dimers and tetramers (mol. wt 64,500) in that of B. alternatus. 5. 5. The Hill plots as a function of O2 tension show for B. alternatus hemolysate a shift from deoxytetramer nH = 2.02 to oxydimer nH = 0.88 as occurs in L. miliaris. For B. constrictor hemoglobin the nH remains 1.0 independent of the O(in2) tension. |
