= Heparinase
<Heparinase> is a name for a heparin-cleaving <enzyme>, classified as heparin lyase in the enzyme nomenclature. It breaks specified <glycosidic bonds> in <heparin>-type <polysaccharides> by eliminative cleavage. The reaction identity matters when using the enzyme to perturb a complex cell-surface layer.<Heparin lyase in IUBMB Enzyme Nomenclature>[EC 4.2.2.7, accepted name, reaction and synonym]{ref}
In a 1990 experiment, researchers perfused individual <capillaries> in situ with enzyme-containing solution. <Heparinase> treatment at least doubled tube <hematocrit>, the fraction of the capillary's volume occupied by <red blood cells>, without a significant change in red-cell velocity. Vehicle alone and heat-denatured enzyme did not produce that response.<Heparinase treatment suggests a role for the endothelial cell glycocalyx in regulation of capillary hematocrit by C. Desjardins and B. R. Duling>[Abstract, microperfusion, tube hematocrit and controls]{ref}
The controls connect the response to active enzymatic treatment rather than simply perfusing fluid. The observation supports a contribution of the <endothelial glycocalyx> to red-cell distribution. It does not mean that <hematocrit> and flow velocity are the same quantity, or that one enzyme experiment completely identifies every affected surface component. The substrate specificity and preparation used remain part of the experiment's interpretation.
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