Bacillus subtilis alpha-amylase: the rate limiting step of secretion is growth phase-independent.
When Bacillus subtilis alpha-amylase was expressed under the control of sacR in a degU32(Hy) strain, the production of exoenzyme occurred during both the exponential and stationary phases of growth. In each phase, pulse-chase experiments showed that the rate-limiting step of the secretion process was the release of the processed form of the protein in each physiological context. The rate of this event was slightly slower (t(1/2) = 3.2 min) during the stationary phase than during the exponential phase (t(1/2) = 2 min). The effectors which possibly control the efficiency of the release stage, the level of PrsA or the calcium binding properties of the cell wall, remained unchanged throughout growth phases.
Haddaoui
E
E
Institut Jacques Monod-C.N.R.S, Universités Paris, France.
Chambert
R
R
Petit-Glatron
M F
MF
Lindy
O
O
Sarvas
M
M
D001412:Bacillus subtilis / Q000201:enzymology* / Q000254:growth & development; D001426:Bacterial Proteins; D002118:Calcium / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D007700:Kinetics; D008074:Lipoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D000516:alpha-Amylases / Q000096:biosynthesis / Q000378:metabolism*
D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; C082160:prsA protein, bacteria; D000516:alpha-Amylases; D002118:Calcium