The target of this work is to modify natural rubber by an environmentally friendly process, in order to obtain materials with properties analogous to, or extending those of synthetic rubber. On this basis the route chosen towards the modification of natural rubber was by direct enzyme action. The enzyme chosen for this work was cytochrome P-450 (1.14.14.1), which is an iron-porphyrin-containing monooxygenase. It was obtained for this work from hepatic microsomes. Various incubation procedures for the oxidation of several simple liquid hydrocarbons have been examined, and the conditions optimised. Product yields in excess of 90 % have been obtained using cytochrome P-450 from liver homogenates obtained from rats stimulated by the use of phenobarbital. The highest yields were obtained when NADPH, the natural reducing agent of the enzyme was used. After the incubation conditions had been optimised for the enzymic oxidation of these simple liquid hydrocarbons such as cyclohexane and decane, steps were made towards achieving the enzymic oxidation of liquid hydrocarbons of more similar unit structure to the cis-polyisoprene unit, such as 1-methyl-l-cyclohexene. The successful oxidation of these species has led to progressive oxidation attempts upon larger substrates such as dihydromyrcene, squalene, polybutadiene and natural rubber itself. Although the oxidation of natural rubber by cytochrome P-450 has not yet been achieved, proton-n.m.r. analysis of the products extracted from incubations upon a synthetic liquid cis-polyisoprene sample (m.wt. 30000), has shown that the enzyme has oxidised this species to a small extent @ 0.5 %.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:633069 |
| Date | January 1994 |
| Creators | Auden, Leigh Adams |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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