Methoxyflurane is an anesthetic whose metabolism by cytochrome P-450LM2 has been shown to be dependent upon a heat-stable microsomal protein (Canova-Davis, E., and Waskell, L. A. (1982) Biochem. Biophys. Res. Commun. 108, 1264-1270). Treatment of this protein with diethylpyrocarbonate, which modifies selected amino acids, caused a dose-dependent loss in its ability to effect the metabolism of m...

Plasmids containing long tracts of (dA)n.(dT)n have been prepared and their conformations examined in linear and supercoiled DNA using a series of chemical and enzymic probes which are known to be sensitive to unusual DNA structures. Under superhelical stress and in the presence of magnesium the sequence T69.A69 adopts a conformation at pH 8.0 consistent with the formation of an intramolecular ...

D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was strongly inactivated by diethylpyrocarbonate (DEPC). An H67N mutant was barely active, with a kcat/Km 6.3 x 10(4) times lower than that of the recombinant wild-type enzyme, while the H67I mutant lost detectable activity. The H67N mutant had almost constant Km, but greatly decreased kcat. These results sug...

Isolation of polyribosomes from wheat embryos and corn root tips in the presence of diethyl pyrocarbonate showed this reagent to have a protective effect on polyribosome structure. In addition, the use of diethyl pyrocarbonate allowed initial homogenization to be performed under less stringent conditions than those normally employed for polyribosome isolation. The use of the reagent is however ...

The rapid inactivation of 3-HBA-6-hydroxylase by 100 microM diethylpyrocarbonate or 40 microM N-bromosuccinimide and protection offered by the substrate, 3-hydroxybenzoate, against these chemical modifications implicate the involvement of histidine and tryptophan in the catalytic activity of the enzyme. Inactivation of the enzyme by diethylpyrocarbonate followed pseudo-first-order kinetics, and...

The ability of a number of commonly used inhibitors to inhibit pancreatic ribonuclease has been studied. At ribonuclease concentrations of 10 or 100 g/ml, heparin, polyvinylsulfate and proteinase K, at concentrations reported for their use in the literature, were ineffective in inhibiting RNase digestion of 3H-uridine labelled RNA from Streptomyces antibioticus. In contrast, macaloid, diethylpy...