Although there is an abundance of evidence in support of the template hypothesis of protein biosynthesis (I), there appears to have been no satisfactory experimental basis for deciding whether the role of the template includes the coiling and folding of the protein chain to produce the secondary and tertiary structures’ or is restricted to the formation of amino acid sequence. It has been repor...

Beef pancreas ribonuclease activity is markedly accelerated by increased ionic strength (14). Since certain physical properties of nucleic acids are known to be altered by this factor, it becomes of interest to determine whether salt concentration affects primarily the enzyme, the substrate, or both. A second factor of importance in ribonuclease (RNase) assays is that of substrate concentration...

1. Ribonucleic acid of yeast causes the formation of a potent hemolysin in broth cultures of Streptococcus pyogenes. 2. The hemolysin whose formation is induced by yeast ribonucleic acid appears to be identical with streptolysin S. 3. Desoxyribonucleic acid, products of acid or alkaline hydrolysis of ribonucleic acid, or many other substances tested, fail to produce a similar effect. 4. Digesti...

Alkylation of ribonuclease A by iodoacetamide at pH 5.5 yields two products: inactive 3-carboxamidomethylhistidine12.ribonuclease and fully active S-carboxamidomethylmethionine ribonuclease. No derivative substituted at histidine-119 was detected. This is in marked contrast to the products obtained on alkylation by iodoacetate at pH 5.5. The rate of alkylation of histidine in ribonuclease by io...

In studies on the chemical structure of ribonuclease in which trypsin is used as a specific reagent for hydrolysis (2), it has been found necessary first to cleave the disulfide bridges in the molecule by oxidation with performic acid in a manner similar to that employed by Sanger (3) in his investigation of insulin. Oxidation is required in order to render the protein more readily susceptible ...

found no increase in ribonuclease activity in the postmitochondrial supernatant from the muscle of alloxan-diabetic rats when we followed the conversion of 3zP-labelled rRNA into acid-soluble fragments (Table 1). It is likely therefore that the putative ribonuclease is a relatively specific endonuclease releasing large oligonucleotides which are insoluble in acid. In view of the net breakdown o...

Ribonuclease A has been the most studied enzyme of the twentieth century. Work on ribonuclease A has endowed enzymology, as well as protein science, with many paradigms. This work continues to provide a framework for understanding protein structure – function relationships in atomic detail. In addition, knowledge gained by basic research is enabling the rapid deployment of ribonuclease A homolo...

Cross-linked dimers of ribonuclease, added at a concentration of 0.05 mg/ml to the culture medium of hepatoma (HTC) cells, were previously shown to inhibit intracellular degradation of peroxidase taken up by endocytosis. Intracellular localization showed that endocytosed peroxidase does not reach lysosomes in dimer-treated cells. The present study shows that preloading of lysosomes with fluores...

Endoribonuclease splitting single-stranded poliovirus RNA is associated with virions of the myxoviruses fowl plague virus and Newcastle disease virus. These virions are devoid of deoxyribo­ nuclease hydrolyzing single-stranded M 13 phage DNA and ribonuclease hydrolyzing double­ stranded poliovirus RNA. The latter enzyme, however, is present in allantoic fluids of infected chick embryos from whi...