The rapid degradation of ribonucleic acids (RNA) by ubiquitous ribonucleases limits the efficacy of new therapies based on RNA molecules. Therefore, our aim was to characterize the natural ribonuclease activities on the skin and in blood plasma i.e. at sites where many drugs in development are applied. On the skin surfaces of Homo sapiens and Mus musculus we observed dominant pyrimidine-specifi...

Pancreatic-type ribonucleases show clinical promise as chemotherapeutic agents but are limited in efficacy by the inefficiency of their uptake by human cells. Cellular uptake can be increased by the addition of positive charges to the surface of ribonucleases, either by site-directed mutagenesis or by chemical modification. This observation has led to the hypothesis that ribonuclease uptake by ...

Greene (1) found that the proteins of bovine pancreatic juice and pancreatic zymogen granules contain identical concentrations of a ribonuclease that on chromatography over Amberlite IRC-50 exhibits the behavior of the enzyme previously called (2, 3) ribonuclease B. The present report deals with the isolation of ribonuclease B from bovine pancreatic juice and provides a description of some of i...

Some properties of rat spleen ribonuclease have been studied, and the intracellular distribution of the enzyme and ribonucleic acid have been presented. Spleen ribonuclease exhibits maximal activity at pH 5.8, and although there is some evidence for the presence of an enzyme with an opt imum at pH 7.0, it is not conclusive. The enzyme is concentrated primarily in the mitochondrial fraction, but...

Some properties of rat spleen ribonuclease have been studied, and the intracellular distribution of the enzyme and ribonucleic acid have been presented. Spleen ribonuclease exhibits maximal activity at pH 5.8, and although there is some evidence for the presence of an enzyme with an opt imum at pH 7.0, it is not conclusive. The enzyme is concentrated primarily in the mitochondrial fraction, but...

One of the tightest known protein-protein interactions in biology is that between members of the ribonuclease A superfamily and the ribonuclease inhibitor protein (RI). Some members of this superfamily are able to kill cancer cells, and the ability to evade RI is a major determinant of whether a ribonuclease will be cytotoxic. The archetypal cytotoxic ribonuclease, onconase (ONC), is in late-st...

The occurrence of both acid and alkaline ribonuclease activities in liver and kidney was reported in 1954 by Roth (1) and by de Lamirande et al. (2). Since then, investigators have used various methods to purify the intracellular ribonuclease activities (3-8). In our studies, comparatively mild procedures were used for the nuclease preparations (5)) with the hope that the nuclease activities as...

The major ribonuclease of human liver has been isolated in a four-step procedure. The protein appears homogeneous by several criteria. The amino acid composition and the amino-terminal sequence of the enzyme indicate that the protein is related to human pancreatic ribonuclease and to angiogenin, and that it may be identical with an eosinophil-derived neurotoxin and to a ribonuclease that has be...

The author would like to express his appreciation to Professor Ephraim Katchalski for his hospitality, to Professor Michael Sela for samples from his collection and for valuable discussion, to Professor Franz Sondheimer for the use of a spectrophotometer, and to Dr. Israel Schechter and Mr. Shmuel Shaltiel for valuable advice. Abbreviations used are: pTR, poly-L-tyrosyl ribonuclease; pApTR-L, l...