Chemical modification causes similar change in dependence on water activity of chymotrypsin hydration and catalysis in hexane

D.G. Rees, ll. Gerashchenko, E.V. Kudryashova, V.V. Mozhaev, P.J. Halling

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7 Citations (Scopus)


Amino groups in alpha-chymotrypsin were reacted with pyromellitic anhydride, introducing 17 to 32 additional carboxyl groups. This modification causes a major change in the water adsorption isotherm of the lyophilized protein powder. Little water is bound by the modified enzyme at water activity (a(w)) below 0.35, but it shows increased water binding at a(w) over 0.5. This correlates with a similar change in the a(w) dependence of the catalytic activity of the enzyme powder suspended in hexane, with a much steeper increase in activity of the modified chymotrypsin.
Original languageEnglish
Pages (from-to)161-166
Number of pages5
JournalBiocatalysis and Biotransformation
Issue number3
Publication statusPublished - Jun 2002


  • water adsorption
  • low-water nonpolar media
  • chymotrypsin
  • chemical modification
  • pyromellitic acid
  • Organic media
  • alpha-chymotrypsin
  • enzyme-activity
  • stability
  • solvents
  • protein
  • esterification

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