دورية
Betaine-Homocysteine Transmethylase in Pseudomonas denitrificans, a Vitamin B12Overproducer
| العنوان: | Betaine-Homocysteine Transmethylase in Pseudomonas denitrificans, a Vitamin B12Overproducer |
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| المؤلفون: | White, Raymond F., Kaplan, Louis, Birnbaum, Jerome |
| المصدر: | Journal of Bacteriology; January 1973, Vol. 113 Issue: 1 p218-223, 6p |
| مستخلص: | A pantothenate-methionine auxotroph (J741) of Pseudomonas denitrificanswas isolated whose growth requirement for methionine could not be satisfied by known precursors of the amino acid, including homocysteine. However, some “methyl rich” compounds such as betaine and dimethylacetothetin (DMT) could satisfy the requirement. S-Methyl-methionine and S-adenosylmethionine were ineffective. Extracts were found to contain an enzyme, betaine-homocysteine transmethylase (BHTase), that uses betaine or DMT as a methyl donor and homocysteine as an acceptor to produce methionine. Growth of J741 in methionine leads to a total repression of the BHTase, whereas the use of DMT leads to a three- to sixfold stimulation of enzyme synthesis compared to betaine-grown cells. The pantothenate requirement is unrelated to the methionine auxotrophy, since the growth of other single auxotrophic mutants as well as revertants of J741 still have their methionine requirement satisfied by betaine or DMT. Another methionine auxotroph that could not use betaine for growth was devoid of BHTase activity. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 00219193 10985530 |
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| DOI: | 10.1128/jb.113.1.218-223.1973 |