Kinetics and regulation of cell-free alkaline phosphatase synthesis

Abstract

Regulation of alkaline phosphatase (EC 3.1.3.1) synthesis in a cell-free system from Escherichia coli has been observed. Synthesis from transducing phage deoxyribonucleic acid templates carrying phoA+ occurred in S30 fractions from wild-type or alkaline phosphatase-constitutive mutants. It did not occur in S30) fractions from alkaline phosphatase-negative mutants (phoB). The hybrid gene phoA-lacZ was also subject to phoB control, implying that phoA transcription is regulated. The yield of active alkaline phosphatase per phoA+ gene copy from cell-free synthesis was similar to that of beta-galactosidase. Alkaline phosphatase activity took longer to appear than beta-galactosidase activity. Synthesis of alkaline phosphatase subunits was not delayed, suggesting that a minimum number of subunits are synthesized before formation of active alkaline phosphatase occurs.