| dc.contributor.author | Smith, Kevin Craig. | en_US |
| dc.date.accessioned | 2014-10-21T12:37:15Z | |
| dc.date.available | 1995 | |
| dc.date.issued | 1995 | en_US |
| dc.identifier.other | AAINN08798 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55093 | |
| dc.description | 5-Hydroxy-4-oxo- scL-norvaline (HON) produced by Streptomyces akiyoshiensis is derived from the incorporation of aspartate and the methyl group of acetate. To further elucidate the HON biosynthetic pathway, the culture supernatant of HON mutant L138, which stimulated the production of HON in mutant L127, was examined for the accumulation of biosynthetic intermediates. An assay based on the cosynthetic relationship between L127 and L138 was developed for directing the purification of substances responsible for transforming mutant L127 into a HON producer. During the attempted purification of the L138 metabolite, circumstantial evidence suggested that the L138 metabolite was not consistent with an accumulating intermediate. Cross-feeding experiments using (2-$\sp $C) acetate as a supplement showed that the L138 metabolite was an initiator of de novo HON production in mutant L127. The nature of its binding to various chromatographic media and its extractability into organic solvents suggests that the metabolite is highly polar with a weakly acidic substituent, possibly a phenol. A compound having similar solubility and chromatographic properties to the L138 metabolite is the autoregulator cosynthetic factor 1. | en_US |
| dc.description | An L138 metabolite initially identified as the simulating substance was characterized by spectroscopic methods and found to be identical to a synthetic sample of N-acetyl- scL-dopa. However, synthetic N-acetyl- scL-dopa did not transform mutant L127 into a HON producer. Culture conditions were examined to optimize production of N-acetyl- scL-dopa for biosynthetic investigations. Supplementing cultures with possible precursors scL-tyrosine, N-acetyl- scL-tyrosine or scL-dopa greatly stimulated the production of N-acetyl- scL-dopa but scL-tyrosine stimulated at a lower level. This would be consistent with a larger number of steps required to convert scL-tyrosine to N-acetyl- scL-dopa. Although two possible pathways exist from scL-tyrosine to N-acetyl- scL-dopa, the presence of an acetylating enzyme in cell-free extracts that efficiently acetylates scL-dopa but not scL-tyrosine suggests that scL-dopa is an intermediate of the pathway. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1995. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Microbiology. | en_US |
| dc.subject | Chemistry, Biochemistry. | en_US |
| dc.title | Metabolites of Streptomyces akiyoshiensis and their relationship to HON biosynthesis. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
