. Aspects of the origin of life. Life; Biochemistry; Biochemistry; Biogenesis. 186 G. A. DEBORIN preincubated with NaCl for 45 minutes at 37 °C, after which the curve for proteolysis by trypsin (added after preincubation) was plotted. Curve II is for serum albumin preincubated with DNA, after which the course of proteolysis by trypsin was plotted. Curve III is for trypsin preincubated with NaCI, after which substrate was added and the proteolysis curve plotted then. In the case of curve IV the trypsin was preincubated with DNA, after which proteolysis was plotted for serum albimiin. For curves
. Aspects of the origin of life. Life; Biochemistry; Biochemistry; Biogenesis. 186 G. A. DEBORIN preincubated with NaCl for 45 minutes at 37 °C, after which the curve for proteolysis by trypsin (added after preincubation) was plotted. Curve II is for serum albumin preincubated with DNA, after which the course of proteolysis by trypsin was plotted. Curve III is for trypsin preincubated with NaCI, after which substrate was added and the proteolysis curve plotted then. In the case of curve IV the trypsin was preincubated with DNA, after which proteolysis was plotted for serum albimiin. For curves II and IV the amount of DNA was the same and the DNA/ protein ratio was equal to o-o66; the enzyme/substrate ratio in these experiments was 1 Fig. 6. The effect of preincubation of the enzyme or substrate with DNA on the proteolysis of serum albumin by trypsin (see text) It follows from the experiment that marked inhibition of proteolysis occurred only if there was preliminary incubation of the substrate with DNA, whereas preliminary incubation of the enzyme with DNA had practically no effect on the kinetics of proteolysis. The conclusion to be drawn from these results is that DNA in the senmi albumin-trypsin system affects not the enzyme, but the substrate, producing inhibition of the proteolytic process. The author of the present paper also studied the influence of DNA on pro- teolysis at various DNA/substrate ratios. These findings are given in Fig. 7, where the curve for the proteolysis of serum albumin by trypsin in the absence of DNA served as a control. The DNA/substrate ratio for curves I, II and III is equal to 033, o-66 and 0-99 respectively. It was also found that at a DNA/ substrate ratio equal to i/ioo proteolysis is likewise retarded Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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