A plate assay is described to detect extracellular RNase producing strains. RNA is used in the Petri dish assay for the determination of RNase activity. After growth of the organisms, the agar plate is flooded with a RNA precipitant and enzyme activity is shown by clear zones (halos) around the colonies. The simultaneous use of specific RNase inhibitor like diethyl pyrocarbonate allow the speci...

DNA structural changes induced by bleomycin have been investigated using diethylpyrocarbonate and permanganate as probes under conditions in which the antibiotic binds to, but does not cut the DNA. Diethyl-pyrocarbonate shows an enhanced reaction with adenines in the presence of the antibiotic in the sequences GTA greater than GCA greater than GAA, on the 3' side of the drug cutting site (GPy)....

Currents through the human skeletal muscle chloride channel hClC-1 can be blocked by external application of 1 mM Zn2+ or the histidine-reactive compound diethyl pyrocarbonate (DEPC). The current block by Zn2+ strongly depends on the external pH (pKa near 6.9), whereas the block by DEPC is rather independent of the pH in the range of 5.5 to 8.5. To identify the target sites of these reagents, w...

The pH-dependent kinetics of lysyl oxidase catalysis was examined for evidence of an ionizable enzyme residue which might function as a general base catalyzing proton abstraction previously shown to be a component of the mechanism of substrate processing by this enzyme. Plots of log Vmax/Km for the oxidation of n-hexylamine versus pH yielded pKa values of 7.0 +/- 0.1 and 10.4 +/- 0.1. The highe...

The endogenous argininosuccinate lyase activity of duck delta2-crystallin was specifically inactivated by the histidine-specific reagent, diethyl pyrocarbonate. The protein was protected by l-citrulline or l-arginine from the diethyl pyrocarbonate inactivation. To characterize further the chemical mechanism of the delta2-crystallin-catalysed reaction, deuterium-labelled argininosuccinate was en...

The proton-sucrose symporter that mediates phloem loading is a key component of assimilate partitioning in many higher plants. Previous biochemical investigations showed that a diethyl pyrocarbonate-sensitive histidine residue is at or near the substrate-binding site of the symporter. Among the proton-sucrose symporters cloned to date, only the histidine residue at position 65 of AtSUC1 from Ar...