\n\tSummary
\n\tResults of Studying Human Placental RNase.
\n\tI – Distribution of Enzyme Activity in Protein Fractions From the Tissue Extracts
\n\tHuman placental tissue was ground in the phosphate, tris-HCl and PBS 10 mM buffers with pH 7.2 and in the solution of H2SO4 0.02 M in the ratio of 1 gram of the tissue per 5 ml of the solution. It seemed that a total activity of buffers’ extracts from placenta was 2-fold higher than that of acid extract. Then protein fractions were obtained from PBS and acid extracts (designated as DCNTb and DCNTa, respectively) by precipitation with salt (NH4)2SO4, and ribonucleolytic activity in these fractions was determined. The results of determination of enzyme activity in the obtained fractions revealed that recovery of RNase activity from DCNTa was small (less than 50% of a total activity of the DCNTa), whereas almost all the activity of the DCNTb was recovered in its fractions. Moreover, the fraction precipitated in a zone of salt concentration from 10 to 20% (designated as NT-2a) is the most active from Dental, while the most of DCNTb activity is belonging to the fraction precipitated in 60-80% salt concentration (designated as NT-4b). Comparing distribution and properties of enzyme activity in all the obtained RNase preparations allowed to conclude that NT-4b is the best partially purified preparation of RNase from human placenta. Besides, protein fractions precipitated from DCNTa treated (by boiling for 5 min in the water bath at an adjusted pH of the extract from a value of ~1.2 to the value of 7.2) in the zones of salt concentration 40-60% and 60-80% respectively also possessed high enzyme activity (they were designated as NT-3ab and NT-4ab, respectively). These fractions together with preparation NT-4b will be used for further investigation.
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