Activation and regulation systems for venom phospholipases A2

Lyall, Fiona (1984) Activation and regulation systems for venom phospholipases A2. PhD thesis, University of Glasgow.

Abstract

This thesis was in part a continuation of earlier studies of PLA2 activation by fatty acids and imidazolides (Drainas, Ph.D., 1978) and on the regulation of the enzyme by reaction products and albumin (Camero, M.Sc., 1983). It also involved an investigation into the activation of PLA2 from another source and the consequences of activation in terms of protein modification. Gel electrophoresis and fluorographic techniques confirmed that oleoyl imidazolide covalently binds to PLA2. The activation phenomena found in a chemically defined assay system were confirmed and shown to apply when the enzyme attacked a biological membrane substrate. Both bee and wasp venom PLA2, could be activated by oleoyl imidazolide and fatty acids, and were strongly inhibited by lysolecithin. The role of reaction products and albumin on the modulation of PLA2, is discussed. Studies on the chemistry of acyl imidazolide activation suggested that PLA2 requires one molecule of oleoyl imidazolide for almost complete activation and that this activation is controlled by a group with a pK of about 6.5. Activated PLA2 was protected against inactivation by thiols and trypsin, suggesting that activation of the enzyme is associated with a conformational change in the protein. Chemical modification studies revealed that only activated was protected against the effects of PBPB and the implications of this are discussed.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Molecular biology.
• Subjects: Q Science > QH Natural history > QH301 Biology; Q Science > QH Natural history > QH345 Biochemistry
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Lawrence, Dr. A.J.
• Date of Award: 1984
• Depositing User: Enlighten Team
• Unique ID: glathesis:1984-71771
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 17 May 2019 09:31
• Last Modified: 26 Oct 2022 08:17
• Thesis DOI: 10.5525/gla.thesis.71771
• URI: https://theses.gla.ac.uk/id/eprint/71771