beta-Glucuronidase

Smith, Evelyn Elizabeth Brown (1952) beta-Glucuronidase. PhD thesis, University of Glasgow.

Abstract

1) A method has been devised for the purification of ox liver beta-glucuronidase utilising the interactions of proteins with metallic ions and organic solvents. An 800 fold purification has been achieved by such means with a 5% recovery of the enzyme. 2) The properties of the purified material indicate that beta-glucuronidase is a complex enzyme system with at least three and possibly four independent centres of activity. 3) Virtually complete separation of two of the liver glucuronidase fractions with pH optima at pH 4.5 and 5.2 has been achieved by means of organic solvent fractionation, while preparations overwhelmingly rich in activity at pH 3.4 can also be obtained by such means. 4) Kinetic studies on the fractionated material emphasise the independent nature of the separated entities. Significantly different values for the energies of activation and enzyme substrate dissociation constants have been obtained for such fractions from both liver and spleen, and their behaviour towards various inhibitors also show marked differences. 5) A comparative study of the fractionated liver and spleen glucuronidases indicates that the liver glucuronidases are catalytically more efficient than those of the spleen. 6) No evidence can be adduced to show that deoxyribonucleic acid functions as the coenzyme of either liver or spleen beta-glucuronidase as has previously been suggested. 7) A study of the relationship between liver glucuronidase activity and tissue damage and growth has shown no direct correlation between these factors as has been postulated by earlier workers. 8) Studies on chemically induced rat hepatoma indicate that the glucuronidase activity is lower in hepatoma than in normal liver and this in no way permits the conclusion that increased beta-glucuronidase activities are characteristic of malignant neoplasms. 9) The glucuronide decomposing enzyme of Esch. coli has been identified as a beta-glucuronidase, and a study has been made of a few of the reaction characteristics of this enzyme. 10) The beta-glucuronidase of Esch. coli is physically distinct from the complex enzyme system operative in animal tissues. 11) These results have been discussed in relation to previous work in this field.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Biochemistry
• Date of Award: 1952
• Depositing User: Enlighten Team
• Unique ID: glathesis:1952-78884
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 14:44
• Last Modified: 30 Jan 2020 14:44
• URI: https://theses.gla.ac.uk/id/eprint/78884