Determining selectivity of drugs by quantitative two-dimensional gel analysis. A study of tenidap, piroxicam, and dexamethasone.

In vitro pharmacologic measures of drug specificity are well established, i.e. drug interaction with a specific target such as an enzyme, receptor, or ion channel.

Expression and regulation of the penicillin G acylase gene from Proteus rettgeri cloned in Escherichia coli.

The penicillin G acylase genes from the Proteus rettgeri wild type and from a hyperproducing mutant which is resistant to succinate repression were cloned in Escherichia coli K-12. Expression of both wild-type and mutant P. rettgeri acylase genes in E.

The ebg operon consists of at least two genes.

The ebg operon of Escherichia coli includes a second gene designated ebgB. The ebgB gene product is a 79,000-molecular-weight protein and is expressed coordinately with the ebgA gene product, ebg beta-galactosidase. Insertion of the transposable elements Tn5 and Tn9 into ebgA eliminates the expression of ebgB, suggesting that ebgB is distal to ebgA.

Evolution of a new enzymatic function by recombination within a gene.

Mutations that alter the ebgA gene so that the evolved beta-galactosidase (ebg) enzyme of Escherichia coli can hydrolyze lactose fall into two classes: class I mutants use only lactose, whereas class II mutants use lactulose as well as lactose. Neither class uses galactosylarabinose effectively. In this paper we show that when both a class I and a class II mutation are present in the same ebgA gene, ebg enzyme acquires a specificity for galactosylarabinose.