Water as it applies to the function of enzymes.

Escherichia coli and Saccharomyces cerevisiae can metabolize, grow, and divide over osmotic pressures ranging from 0.24 atm to about 100 atm [Record, T. M. et al. (1999). Trends Biochem. Sci. 23,143-148,190-194; Wood, J. M. (1999). Microbiol. Mol. Bio. Rev. 63, 230-262; Marachal, P. A., and Gervais, P. (1994). Appl. Microbiol. Biotechnol. 42, 617-622]. At the higher end of the range, they perform their functions with difficulty, but they can survive. Over the full span of pressures, the activity of water goes from 0.9998 to 0.93. Neither of the authors can survive at anything like these extremes; some of their enzymes and enzymatic complexes would "fall apart," would either cease to function or would denature. We would very much like to know just how the two microbes manage.