Physics of enzymatic mode of action

Polysaccharide modifying enzymes may generate specific sequence patterns in polymers (e.g. epimerisation), or produce oligomers of a certain length as a result of depolymerisation. We are interested in the kinetics, specificity and mode of action of alginate epimerases and lyases. We also study the sequence specificities of lysozyme depolymerisation of partially N-acetylated chitosans and the mode of action of chitin deacetylases. The systems are studied using NMR, dynamic force spectroscopy and simulations. The alginate epimerase AlgE4 produces an alginate with long stretches of alternating MG sequences. The kinetics of formation of this sequence pattern could not be accounted for by a random attack model. Results obtained from dynamic force spectroscopy indicated a processive mode of action. This enzyme might thus be the first known polysaccharide modifying processive enzyme

References:

• Biochemical analysis of the processive mechanism for epimerisation of alginate by mannuronan C-5 epimerase AlgE4
  Campa, C., Holtan, S., Nilsen, N., Bjerkan, T. M., Stokke, B.T. and Skjåk-Bræk, G.
  Biochem. J. 381 (2004) 155-164.