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Investigation of the peptides produced from human elastin by digestion with neutrophil elastase and with cathepsin G

Emphysema is a degenerative lung disease which, it is suggested, results probably from repeated periods of proteinase:antiproteinase imbalance during which excess of enzyme attacks the extracellular matrix. Of the many enzymes produced by inflammatory cells human neutrophil elastase (HNE) is thought to be the major offending enzyme. It attacks elastin, which is responsible for the elastic recoil of the lung. If emphysema was simply a result of the destruction of elastin by HNE then degradation products of elastin would inevitably be present, at least transiently, in the serum of patients. The aim of this project was to separate and characterise the soluble peptides resulting from the digestion of elastin with HNE and/or human neutrophil cathepsin G (HNCG), another neutrophilic enzyme, which is primarily bactericidal and, to determine if any of the peptides were characteristic of digestion by one enzyme or combination of enzymes. HNE and HNCG were isolated from purulent sputum, and elastin was isolated by two methods from post-mortem lungs. The digestion of the elastin by the enzymes was followed by measuring the amino groups liberated during the course of the digestion. A method was developed for the measurement of the insoluble as well as the soluble products of digestion. Initially, the amounts of soluble and insoluble products were similar, but the amount of soluble products soon exceeded the amount of insoluble products. The soluble products of digestion were separated by reverse-phase chromatography. The peptides separated into two groups (A and B), regardless of which enzyme was involved in the initial digestion. Both groups were heterogeneous mixtures of peptides. Filtration experiments and amino acid analysis showed that the groups of peptides differed in size and composition.
Date January 1992
CreatorsHannah, Sharon
PublisherUniversity of Edinburgh
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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