Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.44 (AGT)
 770 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Direct double-strand breaks in DNA have been implicated in cellular lethality of the antitumor antibiotic neocarzinostatin, but the mechanism of their formation has not been elucidated. Evidence is presented that neocarzinostatin causes sequence-specific direct double-strand breaks whose formation is strongly influenced by the activating thiol. Seven-fold more double-strand breaks result when glutathione rather than 2-mercaptoethanol is used to activate the drug to its putative diradical form, while the sequence specificity of cleavage remains the same. These data explain earlier inconsistencies in the ratios of double-strand to single-strand breaks obtained from in vitro and in vivo studies. Double-strand cleavage sites, occurring predominantly at GT steps, especially AGT.ACT, consist of trinucleotide sequences with a two-nucleotide 3'-stagger of the cleaved residues. The chemical structures of the cleavage sites suggest a model in which a neocarzinostatin-induced double-strand break results from abstraction of a C5' hydrogen atom from the T of ACT and the C4' hydrogen atom of the T of AGT by a single molecule of the diradical form of the drug. Single-strand breaks at these sites occur as separate events with attack at the C5' hydrogens. These findings permit the generalization that single-strand breaks produced by neocarzinostatin show a base preference but no clear sequence specificity, while bistranded lesions are sequence-specific in nature.
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PMID:Sequence-specific double-strand breakage of DNA by neocarzinostatin involves different chemical mechanisms within a staggered cleavage site. 214 79

Serological activity of swine IgM and IgG against Brucella abortus in RBPT was determined in relation to four other reactions used in Poland for diagnosing brucellosis standard agglutination test, complement fixation test, antiglobulin test, 2-mercaptoethanol test). Isolation of IgG was performed by the method of filtration on Sephadex gel G-200 of swine sera raised against Brucella abortus S19 by double immunization with suspension of killed bacteria. The presence of a certain Ig class in the fractions thus obtained was confirmed by immunoelectrophoresis and immunodiffusion tests. RBPT revealed the reaction of antibodies of IgM and IgG class which proves usability of this reaction diagnosis both early (IgM) and chronic (IgG) infection with brucellosis. Both classes of antibodies mentioned above were active also in SAT and CTT. Also the results obtained in AGT and MET were found interesting. In one of the sera, the absence of incomplete antibodies was observed, whereas positive reaction in antiglobulin test was found in its fractions containing IgG. This phenomenon was determined as concealment of incomplete agglutinins through higher level of complete antibodies in normal serum. In swine (the results were different from those obtained for cattle), apart from incomplete antibodies in IgG class, the presence of these agglutinins in IgM class was noted. On the other hand, the results obtained in MET proved that IgM antibodies of swine were not totally reduced when affected by 2-mercaptoethanol.
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PMID:[Activity of porcine anti-Brucella abortus immunoglobulins in the acid plate agglutination test (APAT)]. 313 34