Activation of a heparin-degrading enzyme by a 'protein matrix' effect

An unusual activating effect of protein on Flavobacterium heparinase is described. The phenomenon is nonselective with respect to protein species, but does not occur with other biomolecules such as nucleic acids, polysaccharides, or free amino acids. We show that protein activates heparinase over broad ranges of temperature and ionic strength, and stabilizes the enzyme against both reversible and irreversible structural changes. The nonselective activation of an inducible enzyme by protein may be an important regulatory mechanism in microenvironments in which the concentration of organic material may vary.