Specific anion effects on enzymatic activity in nonaqueous media

Dagmar Bilaničová, Andrea Salis*, Barry W. Ninham, Maura Monduzzi

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    62 Citations (Scopus)

    Abstract

    The present work shows that salt anions affect the activity of Pseudomonas cepacia lipase both in aqueous and in nonaqueous media (NAM) according to a Hofmeister series. The biocatalytic assay in water was the hydrolysis of p-nitrophenyl acetate, whereas the esterification between 1-hexyl-β-D- galactopyranoside and palmitic acid was followed in an organic solvent. The solid lipase preparations to be used in NAM were obtained through lyophilization in the presence of concentrated solutions of Hofmeister salts (Na 2SO4, NaH2PO4/ Na 2HPO4, NaCl, NaBr, Nal, NaSCN). Salts affect enzyme activity in organic media through two mechanisms: (1) enzyme protection during lyophilization; (2) enzyme activation during the reaction. At least in our case, the latter seems to be more important than the former. The decrease of the activation energy caused by the stabilization of the transition state due to "kosmotropic" anions might be the driving force of enzyme activation. According to the most recent findings, dispersion forces may be responsible of specific anion enzyme activation/deactivation in NAM.

    Original languageEnglish
    Pages (from-to)12066-12072
    Number of pages7
    JournalJournal of Physical Chemistry B
    Volume112
    Issue number38
    DOIs
    Publication statusPublished - 25 Sept 2008

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