Quantitative affinity chromatography on uridine-5'-(Sepharose-4-aminophenylphosphoryl)-2'(3')-phosphate was developed for the study of binding of ribonuclease species to nucleotide ligands. Elution of the native species ribonuclease-A and -S on the afffinity matrix in 0.4 M ammonium acetate, pH 5.2, containing various amounts of the soluble competing ligand 2'-cytidine monophosphate, reveals an...

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...

The cDNA that codes for cow pancreatic ribonuclease A has been cloned and expressed in the yeast S. cerevisiae. Site-directed mutagenesis of conserved residues Lys41 and ASP121 has been used to probe catalysis by the enzyme. In addition, mutation of Lysl to cysteine has allowed for the covalent attachment or a DNA oligonucleotide that confers sequence specificity on ribonuclease A. Finally, a n...

The endoplasmic reticulum (ER) stress sensor, IRE1, contains a kinase domain and a ribonuclease domain. Ribonuclease mediates the unconventional splicing of mRNA encoding the transcription factor AtbZIP60 in Arabidopsis, or OsbZIP50 in rice, and thereby transduces signals from stressed ER. Here, we demonstrate the additional roles of plant IRE1 using genetically modified rice plants. Using a ge...

Aeropyrum pernix contains one homolog of ribonuclease H (RNase H), A. pernix RNase HII (Ape-RNase HII). Activity characterization showed that Ape-RNase HII exhibited the highest activity in the presence of 5 mM Mn(2+), 1 mM Co(2+), or 10 mM Mg(2+), respectively; however, its cleavage efficiencies at different cleavage sites for Mn(2+) and Mg(2+) were different. Ape-RNase HII cleaved 12-bp RNA/D...

Onconase (ONC) is an amphibian member of the bovine pancreatic ribonuclease (RNase A) superfamily that exhibits innate antitumoral activity. ONC has been granted both orphan-drug and fast-track status by the U.S. Food and Drug Administration for the treatment of malignant mesothelioma, and is poised to become the first chemotherapeutic agent based on a ribonuclease. Investigations into the mech...

David Harker (1906–1991) was an American crystallographer. He a pioneer in the determination of protein structures. and his colleagues determined structure ribonuclease, which first US laboratory. They introduced important innovations crystal analysis, some proved to be forerunners direct methods. For many years, research among dominating factors internationally crystallography.

Immunotoxins are targeted therapeutics designed to kill cancer cells. The targeting moiety of an immunotoxin selectively binds to a tumor cell and targets it for death via an attached toxin. Because the toxins are typically of plant or bacterial origin, their clinical use is limited by immunogenicity and nonspecific toxicity. To circumvent these problems, we have begun to engineer immunotoxins ...

One of the four titrating histidine ring C-2 proton resonances of bovine pancreatic ribonuclease has been assigned to histidine residue 12. This was accomplished by a direct comparison of the rate of tritium incorporation into position C-2 of histidine 12 of S-peptide (residues 1 to 20) derived from ribonuclease S, with the rates of deuterium exchange of the four histidine C-2 proton resonances...