. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FROG EGG PHOSPHOPROTEIN PHOSPHATASE 245. 310 320 330 340 JXIO5 350 360 FIGURE 9. Arrhenius plots for PPPase reaction. Upper curve: phosvitin (10 mM P) as substrate. Lower curve: heated yolk platelets (20 mM P) as substrate. Incubations in M NaCl, pH Incubation period, 10 minutes. The heavily contaminated YPB preparations also had a higher RNA phosphate content than clean yolk fractions (Table I), and it is suggested that the small quan- tities of RNA measured in all the yolk fractions may be due to adsorption of nuc
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FROG EGG PHOSPHOPROTEIN PHOSPHATASE 245. 310 320 330 340 JXIO5 350 360 FIGURE 9. Arrhenius plots for PPPase reaction. Upper curve: phosvitin (10 mM P) as substrate. Lower curve: heated yolk platelets (20 mM P) as substrate. Incubations in M NaCl, pH Incubation period, 10 minutes. The heavily contaminated YPB preparations also had a higher RNA phosphate content than clean yolk fractions (Table I), and it is suggested that the small quan- tities of RNA measured in all the yolk fractions may be due to adsorption of nucleic acids. Properties of yolk, such as P/N ratios, the presence or absence of enzymes, the number of electrophoretic, ultracentrifugal and serological components, may need re-examination because of the instability of the material prepared for characteriza- tion. The wide variations in P/N ratios reported ( to ) (McClendon, 1910; Faure-Fremiet and du Streel, 1921; Lawrence et al, 1943; Panijel, 1950; Gross and Gilbert, 1956; Ringle, 1960) may be related to whether the yolk was carefully cleaned before solubilization and re-precipitation or was first extracted and then re-precipitated. The presence of PPPase reported by L. J. Earth (1956) in yolk extracts may be correlated with the adsorption of pigment and with non- enzymatic dephosphorylation. The variable number of electrophoretic, serological and ultracentrifugal components reported for yolk may also be correlated with the dissociation of the yolk proteins following dephosphorylation. Earth and Earth (1954) estimated that the non-phosphoprotein component of yolk made up approxi- mately 90% of the total protein of the yolk. The possibility that part of their yolk preparations was dephosphorylated during preparation is suggested by the results of this study. Thus, the YPB preparations were found to be unstable and dephos-. Please note that these images are extracted from scanned page images that may have been digitally
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