α-AMYLASE FORMATION IN GROWING AND NONGROWING CELLS OF PSEUDOMONAS SACCHAROPHILA

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Abstract
Cultures growing on a complete medium containing starch synthesize amylase to the extent of approximately 0.1% of the total cellular protein formed. By contrast, cells induced under nongrowing conditions form comparable amounts of enzyme with no measurable increase in total cellular protein. Studies with labeled phosphate and labeled sulfate showed these to be incorporated to an extent about 25 times larger into growing than into nongrowing cells, both forming approximately equal amounts of amylase. Extensive cellular lysis and resynthesis is thus ruled out as a basis for enzyme formation in nongrowing cells. Calculations of possible cellular protein turnover under these conditions are not in accord with recorded rates in other microrganisms. These results are consistent with the hypothesis that amylase formation in resting cells represents a preferential synthesis of this enzyme.