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In the present paper, we report that transcription affects the location of a DNA target in Escherichia coli K-12. A strain whose chromosome had been engineered to encode a lac repressor-GFP (green fluorescent protein) fusion was used as a host for a low copy number plasmid that carries an array of five lac operator sites. Individual cells of this strain… (More)
Methods are described for the isolation and purification of pepsinogen D, a minor zymogen occurring to the extent of about 5% of the potential proteolytic activity in neutral extracts of the pig gastric mucosa. The physical and chemical properties of this zymogen indicate that it is very similar to, if not identical with, dephosphopepsinogen.
Polyamine-biosynthesis activity is known to be negatively regulated by intracellular polyamine pools. Accordingly, treatment of cultured L1210 cells with 10 microM-spermine rapidly and significantly lowered ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) activities in a sequential manner. By contrast, treatment for 48 h with… (More)
Methods are described for the isolation and purification of pepsin D, an enzyme which accounts for about 10% of the enzymic activity in commercial preparations of pepsin. Pepsin D is similar to pepsin in having a molecular weight of about 35000, the same C-terminal amino acid sequence, and an N-terminal isoleucine residue. It differs in having no phosphate… (More)