S. typhimurium strain TA98/1,8-DNP₆ is resistant to mutagenesis by 1,8-dinitropyrene and is deficient in an acetyl-CoA dependent acetyltransferase activity. Strains TA98 and TA98NR which are acetyltransferase competent are sensitive to 1,8-dinitropyrene mutagenesis. The coincidence of acetyltransferase deficiency and 1,8-dinitropyrene resistance in strain TA98/1,8-DNP₆ implicates acetylation as an important process in the metabolic activation of 1,8-dinitropyrene to a mutagenic intermediate. The acetyltransferase activity can be assayed by observing the formation of 1-N-acetylamino-8-aminopyrene and 1,8-N,N'-diacetyldiaminopyrene from 1,8-diaminopyrene. Reduction of the nitro-function is also an important enzymatic step involved in the activation of 1,8-dinitropyrene. Evidence is presented which suggests that a nitroreductase-acetyltransferase enzyme complex may exist. Further investigations of nitroreductase activity have yielded results which indicate that three distinct nitroreductases exist, one specific for 1,8-dinitropyrene, one specific for 1-nitropyrene and one specific for nitrofurazone. The implications of these findings are discussed and an explanatory model is proposed. / Thesis / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22949 |
| Date | 09 1900 |
| Creators | Orr, Joan |
| Contributors | McCalla, D. R., Biochemistry |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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