Study of a proteolytic enzyme from rabbit spleen

Abstract

of Smith (1959) suggest, however, that the combination velocity rates may be determined chiefly by the chemical configuration of the haems, which apparently all combine with the same site on the protein surface (Rossi-Fanelli & Antonini, 1959b), though not necessarily forming identical linkages. Determinations have shown that the ultracentri- fugal molecular weight is the same in all three cases, so that the lower degree of haem-haem interaction shown by mesohaemoglobin and deuterohaemoglobin cannot be attributed to splitting to half-molecules. The results reported here suggest that experiments with more widely different haems may help in understanding the mechanism of haemoglobin function. SUMMARY 1. The rates of combination of natural and reconstituted protohaemoglobin with carbon mon- oxide have been compared both for the first and fourth molecules of carbon monoxide to combine. The natural and reconstituted proteins give rates agreeing with one another.