Action of Bacterial Sialidases

The simplest substrate in general use for measurement of the kinetic constants, Km and Vmax for bacterial sialidase has been sialyllactose, that particular isomer in which sialic acid is in a, 2 3 linkage to 

FIGURE 1. Initial velocity-pH relationship for V. cholerae sialidase. Assay mixtures containing 0.10 /Ltg of enzyme protein, 3 x lO m Gmi, Goia, Goib, Gti and 4 mM Ca + were prepared in 0.01 m Tris, which had been adjusted to the desired pH values with HO Ac in the presence and absence of added strong electrolyte (NaCl). Curve a, 0.01 m Tris-acetate alone curve b, 0.01 m Tris-acetate containing 0.10 m NaCl. 

in some respects, it is possible to generalize concerning the mode of action of bacterial sialidases, but in numerous instances, the various bacterial enzymes show important differences, and inferences may not be made, as is done too often, concerning still uncharacterized bacterial sialidases based upon findings with Clostridium or Vibrio sialidases, or both. To date, the bulk of detailed study has been performed on these two latter examples. Certain other details and an extensive bibliography may be found in the comprehensive reviews by Drzeniek (1972 1973) and Gottschalk and Drzeniek (1972). 

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Thobhani S, Ember B, Siriwardena A, Boons GJ (2003) Multivalency and the mode of action of bacterial sialidases. J Am Chem Soc 125 7154-7155... 

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