منابع مشابه
Chemical carcinogens in non-enzymatic cytosine deamination: 3-isocyanatoacrylonitrile
Uracil has long been known as the main product of nitrosative cytosine deamination in aqueous solution. Recent mechanistic studies of cytosinediazonium ion suggest that the cation formed by its dediazoniation can ring-open to N-protonated (Z,s-cis)-3-isocyanatoacrylonitrile 7. Stereochemical preferences are discussed of the 3-isocyanatoacrylonitriles (Z,s-cis)-10, (E,s-cis)-11, (Z,s-trans)-12, ...
متن کاملDNA cytosine methylation and heat-induced deamination.
The heat-induced conversion of 5-methylcytosine (m5C) residues to thymine residues and of cytosine to uracil residues in single-stranded DNA was studied. The calculated rates for deamination at 37 degrees C and pH 7.4 were approximately 9.5 X 10(-10) and 2.1 X 10(-10) sec-1, respectively. N4-Methyldeoxycytidine, which is in the DNA of certain thermophilic bacteria, was more heat-resistant than ...
متن کاملThe Enzymatic Deamination of Amphetamine
A previous st,udy on the metabolism of amphetamine (1-phenyl-2-aminopropane), widely used as a stimulant of the central nervous system, showed that its major route of biotransformation in the rat and dog involved hydroxylation of the aromatic ring. In the rabbit, however, the compound was not hydroxylated, but was found to be transformed in another manner (2). The present report describes an en...
متن کاملNitrosative cytosine deamination. An exploration of the chemistry emanating from deamination with pyrimidine ring-opening.
A discussion of nitrosative deamination of cytosine 1 is presented that argues for the formation of 6 by diazotization of 1 to cytosinediazonium ion 2 and its electrostatic complex 3, dediazoniation to 4 <--> 5, and amide-bond cleavage to 6. The reaction channels available to 6 include hydrolytic deglycation to 3-isocyanatoacrylonitrile 7, water addition to carbamic acid 9 with the possibility ...
متن کاملMechanism of nitric oxide induced deamination of cytosine.
A five-step mechanism is proposed for the NO -induced deamination of cytosine. It has been investigated using DFT calculations, including both explicit water molecules and a bulk solvent model to mimic an aqueous environment. According to this mechanism, cytosine first undergoes tautomerization with the assistance of a water molecule from the bulk. A NO(+) cation produced by the autooxidation o...
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ژورنال
عنوان ژورنال: Molecular Cell
سال: 2002
ISSN: 1097-2765
DOI: 10.1016/s1097-2765(02)00750-5