Interaction of (3'-/sup 3/H)ClUTP with ribonucleotide reductase (RTPR): evidence for an enzyme catalyzed net 1,2 H-shift to produce (2'-/sup 3/H)3'-keta dUTP
Incubation of (3'-/sup 3/H)ClUTP with prereduced RTPR in the presence of NaBH/sub 4/ resulted in trapping of (/sup 3/H)3'-keto dUTP. Degradation of the reduced ketone by a combination of enzymatic and chemical methods indicated that the hydrogen originally present in the 3' position of ClUTP is on occasion transferred to the 2' position of the 3'-keto dUTP. RTPR catalyzes a net 1,2 H shift. In addition to the production of 3'-keto dUTP, production of dUTP also occurs in 1 out of every 1600 turnovers. Incubation of (2'-/sup 3/H)ClUTP with prereduced RTPR gives results consistent with rapid enolization of 3'-keto dUTP prior to uracil release, rather than trans elimination of the 2'-..cap alpha..-H of 3'-keto dUTP. Incubation of RTPR with ClUTP in the presence of ethanethiol allowed trapping of 2-methylene-3(/sup 2/H) furanone, the species proposed to be responsible for inactivation of RTPR. The trapped 2((ethylthio)methyl)-3 (/sup 2/H) furanone is identical by /sup 1/H NMR spectroscopy to material synthesized chemically. The implications of these results will be discussed in terms of the function of AdoCbl.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 5332781
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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