Abstract:
:The polymerization of deoxynucleoside triphosphates, catalyzed by terminal deoxynucleotidyl transferase from calf thymus gland, is strongly inhibited by various metal chelators. The reaction appears to be first order with respect to enzyme, deoxynucleoside triphosphate, and initiator, indicating that there is only one catalytic center for each enzyme molecule. The presence of metal chelator does not affect the molecular state of the enzyme or the order of reaction. An analysis of the kinetics of o-phenanthroline inhibition demonstrates that the ligand is noncompetitive with nucleoside triphosphate substrate and strictly competitive with oligodeoxynucleotide initiator. These results, obtained in the presence of millimolar Mg(++), suggest that the initiator binds to the enzyme through a transition metal atom and ligand inhibition occurs at that site. The precise spatial arrangement of the coordination orbitals around a metal atom provides a model to visualize the specificity of the enzyme for the 3'-OH end of the growing polynucleotide chain.
journal_name
Proc Natl Acad Sci U S Aauthors
Chang LM,Bollum FJdoi
10.1073/pnas.65.4.1041subject
Has Abstractpub_date
1970-04-01 00:00:00pages
1041-8issue
4eissn
0027-8424issn
1091-6490journal_volume
65pub_type
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1993-05-15 00:00:00