. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SECRETORY GRANULES OF PYLORIC CAECA 71. B D FIGURE 9. Electrophoretic separation of the casein-hydrolyzing activities: a, pyloric caeca homogenates; b, 4300 X g sediment of the homogenates; c-f, supernatant, M, M and sediment fractions obtained by sucrose density gradient centrifugation of the 4300 X g sedi- ment, respectively. No significant change in the electrophoretic pattern occurred during separa- tion of the secretory granules. performed with the freshly prepared fraction. On the other hand, the enzyme was act
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SECRETORY GRANULES OF PYLORIC CAECA 71. B D FIGURE 9. Electrophoretic separation of the casein-hydrolyzing activities: a, pyloric caeca homogenates; b, 4300 X g sediment of the homogenates; c-f, supernatant, M, M and sediment fractions obtained by sucrose density gradient centrifugation of the 4300 X g sedi- ment, respectively. No significant change in the electrophoretic pattern occurred during separa- tion of the secretory granules. performed with the freshly prepared fraction. On the other hand, the enzyme was activated rapidly by incubation at 37° C. The activation also occurred at 4° C, though it required longer duration (Fig. 8). This suggests that the enzyme activation may be physiologically possible in poildlothermal animals. The results presented in Figure 8 also show that solubilization of the en/.ymes by homogeniza- tion alone would not cause their instantaneous activation, that the activation might be an enzyme-catalyzed reaction, and that the enzymes exist in easily-solubilized forms and are not bound to the granular membranes. The specific activity of the M fraction was nine times, and that of the supernatant obtained from the M fraction \vas thirty-five times greater than that of the original tissue homogenates (Table I). Electrophoretic patterns of the activated enzymes were almost the same in all fractions obtained during purifica- tion (Fig. 9). The data excluded the possibility that particular forms of the enzymes were selectively isolated during purification. By electron microscopy, the M fraction contained numerous granules, the morphology of which were the same as those of the secretory granules in tissues. Some contaminated elements, such as smooth-surfaced vesicles, mitochondria and storage granules usually appeared in these fractionated specimens. Many secre- tory granules were present separately, but some were isolated in the form of clumps, surround
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