Kinetic analysis of rabbit liver tRNA nucleotidyltransferase.
نویسندگان
چکیده
منابع مشابه
Kinetic analysis of rabbit liver tRNA nucleotidyltransferase.
The kinetic properties of rabbit liver tRNA nucleotidyltransferase were examined. Our results indicate that incorporation of AMP into tRNA-C-C at pH 9.4 proceeds by a rapid equilibrium Random Bi Bi mechanism. This conclusion was supported by bisubstrate initial velocity studies, dead end and product inhibition, and isotope exchange at equilibrium and during the net reaction. This analysis has m...
متن کاملPolyamine stimulation and cation requirements of rabbit liver tRNA nucleotidyltransferase.
We have examined the cation requirements of rabbit liver tRNA nucleotidyltransferase. The enzyme had an absolute requirement fo a divalent cation which could be satisfied by Mg2+, Mn2+ or Co2+. In contrast to the Escherichia coli enzyme, we have found no evidence to implicate Zn2+ in the action of rabbit liver tRNA nucleotidyltransferase. We have also identified a second cation requirement whic...
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There has been increased interest in bacterial polyadenylation with the recent demonstration that 3' poly(A) tails are involved in RNA degradation. Poly(A) polymerase I (PAP I) of Escherichia coli is a member of the nucleotidyltransferase (Ntr) family that includes the functionally related tRNA CCA-adding enzymes. Thirty members of the Ntr family were detected in a search of the current databas...
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tRNA CCA-termini are generated and maintained by tRNA nucleotidyltransferases. Together with poly(A) polymerases and other enzymes they belong to the nucleotidyltransferase superfamily. However, sequence alignments within this family do not allow to distinguish between CCA-adding enzymes and poly(A) polymerases. Furthermore, due to the lack of sequence information about animal CCA-adding enzyme...
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The CCA-adding enzyme repairs the 3'-terminal CCA sequence of all tRNAs. To determine how the enzyme recognizes tRNA, we probed critical contacts between tRNA substrates and the archaeal Sulfolobus shibatae class I and the eubacterial Escherichia coli class II CCA-adding enzymes. Both CTP addition to tRNA-C and ATP addition to tRNA-CC were dramatically inhibited by alkylation of the same tRNA p...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1978
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(17)34496-4