Cobalamin-dependent and cobamide-dependent methyltransferases
نویسندگان
چکیده
منابع مشابه
Cobalamin Binding and Cobalamin-Dependent Enzyme
This work was presented in part at the meeting ofthe American Society of Human Genetics, San Diego, Calif., October 1977. Dr. Mellman and Dr. Willard are recipients of traineeships from the National Institutes of Health (T01-GM 02299). Dr. Mellman's present address is Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York 10021. Received for publication 18 May 19...
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Cobalamin-dependent methionine synthase catalyzes the transfer of a methyl group from N5-methyltetrahydrofolate to homocysteine, producing tetrahydrofolate and methionine. Insufficient availability of cobalamin, or inhibition of methionine synthase by exposure to nitrous oxide, leads to diminished activity of this enzyme. In humans, severe inhibition of methionine synthase results in the develo...
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The B12 or cobalamin coenzymes are complex macrocycles whose reactivity is associated with a unique cobalt-carbon bond. The two biologically active forms are MeCbl and AdoCbl and their closely related cobamide forms. MeCbl participates as the intermediate carrier of activated methyl groups. During the catalytic cycle the coenzyme shuttles between MeCbl and the highly nucleophilic cob(I)alamin f...
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Queuosine (Q) was discovered in the wobble position of a transfer RNA (tRNA) 47 years ago, yet the final biosynthetic enzyme responsible for Q-maturation, epoxyqueuosine (oQ) reductase (QueG), was only recently identified. QueG is a cobalamin (Cbl)-dependent, [4Fe-4S] cluster-containing protein that produces the hypermodified nucleoside Q in situ on four tRNAs. To understand how QueG is able to...
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Candida utilis has been shown to contain 4.7 pmol of cobalamin per g of wet cell paste. Purification of the cobalamin showed it to be a mixture of methylcobalamin and adenosylcobalamin. Two cobalamin-dependent enzyme systems have been found in the yeast: methylcobalamin-dependent methionine biosynthesis and leucine 2,3-aminomutase. The cobalamin extracted from the yeast is as effective as authe...
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ژورنال
عنوان ژورنال: Current Opinion in Structural Biology
سال: 2008
ISSN: 0959-440X
DOI: 10.1016/j.sbi.2008.11.005