Human sputum elastase

Human leukocyte elastase (HLE EC 3.4.21.37 also known as human neutrophil elastase, HNE) [1] is a strongly basic glycoprotein which is produced by polymorphonuclear leukocytes (neutrophils) and is released from their azurophilic granules [2]. HLE exists as at least four distinct isozymes, which range in molecular weight from 24 [3] to 30 kDa [4] and appear to differ only in carbohydrate content [5]. Furthermore, human sputum elastase (HSE), which is isolated from purulent sputum as at least five distinct isozymes [6], is both immunologically and catalytically indistinguishable from HLE [7] and is believed to be identical to it. 

Some protoberberine and structurally related alkaloids were tested for inhibitory activity on porcine pancreatic elastase (PPE) and human sputum elastase (HSE). Berberine chloride significantly inhibited the elastolytic activity of both enzymes, but tetrahydroberberine had no effect. It appears that the quaternary nitrogen atom of these alkaloids plays an important role in the inhibition of elastolytic activity. The amidolytic activity of the elastases was not affected by any of the test alkaloids [240]. 

Cook, L., Ternai, B., Ghosh, P. Inhibition of human sputum elastase by substituted 2-pyrones. J. Med. Chem. 1987, 30, 1017-1023,... 

---