血合筋肉の化学的研究-XIII

Abstract

Alkali denaturation curves of hemoglobin (Hb) and myoglobin (Mb) of fishes were determined mainly in oxy form under various conditions. The results obtained were as follows. Denaturation curves of oxy-Hb of the fishes except flathead appeared between those of horse (fairly resistible Hb among mammalian Hb's2, 10)) and human Hb (least resistible Hb2, 10)) (Fig. 7). Therefore, there seems to be no clear inter-specific specificity of Hb between fishes and mammals in the alkali resistibility. Specificity may be pointed out, however, on the shape of the denaturation curve; the curves of mammalian Hb's were almost straight, indicating that the denaturation was of the first order reaction, whereas those of fish Hb's were not. The alkali denaturation curves of fish Hb's were different considerably from one another, both in the slope and in the shape of them. Thus the alkali resistibility may be regarded as one of the representations of intra specific specificities of fish Hb. Though Hb's of many fishes showed gently curved lines, those of some fishes such as carp, mullet, big-eye tuna, and chum salmon presented sharply bended lines, just as suggesting that they are consisting of two components different in alkali resistibility. Hb's of carp and mullet are, however, electrophoretically homogeneous6). Although two Hb's were seen also on electrophoresis in the case of chum6), the proportion of both components as estimated from its denaturation curve was not agreeable with that calculated from the electrophoretic pattern. In addition, as seen in the case of carp (Fig. 6), the shape of the denaturation curve was markedly different at various pH's. Because of these facts, the alkali denaturation method may be not so useful to analysis of multiple Hb's of fish. Met-Mb of tuna was much more resistant to alkali denaturation than met-Hb of the same fish (Fig. 10). In order to investigate whether the difference in alkali resistance between both pigments of tuna is applicable to the simultaneous determination of them as previously described in the case of human7), experimental conditions (such as derived form of pigments, pH, and time of reaction) under which Mb remains native and Hb denatures completely, were looked for in vain (Figs. 9 and 11, Table 1).