Kinetics of Polymerization and Phosphorolysis Reactions of Escherichia coli Polynucleotide Phosphorylase. Evidence for Multiple Binding of Polynucleotide in Phosphorolysis
نویسندگان
چکیده
منابع مشابه
Phosphorolysis of oligoribonucleotides by polynucleotide phosphorylase.
This reversible reaction has been demonstrated With enzyme preparations from Azotobacter trinelundii (1, 2) and Escherichia coli (3). In the forward direction the enzyme catalyzes the formation of polyribonucleotides similar in structural details to natural RNA1 (5-8). In the reverse reaction polyribonucleotides are phosphorolyzed to yield nucleoside diphosphates. The phosphorolysis of syntheti...
متن کاملThe effect of chain length on the phosphorolysis of oligonucleotides by polynucleotide phosphorylase.
The kinetics of phosphorolysis of compounds in the series (Ap),A (II = 2 to 8), p(Ap),A (n = 2 to 4), and (Up)I;cT, (II = 3 to 6) has been studied. K, and V,,, values were obtained for all compounds. K, decreases with increasing chain length and reaches a minimum value with compounds containing 5 phosphate residues. With the shorter compounds the dependence of K, on the nucleoside residues is a...
متن کاملIsolation and mapping of polynucleotide phosphorylase mutants of Escherichia coli.
Three strains of Escherichia coli with altered polynucleotide phosphorylase, Q7, Q13, and Q27, were isolated by screening clones from heavily mutagenized cultures for low levels of the enzyme. The three mutations were found to cotransduce with argG and asp, and the pnp locus which they define was mapped with respect to these loci. An explanation for the nonreciprocal cotransduction frequencies ...
متن کاملPurification and properties of polynucleotide phosphorylase from Escherichia coli.
A method for the purification of polynucleotide phosphorylase from Escherichia coli has been developed. The purified enzyme has a specific activity 700-fold higher than the crude extract. When enzyme fractions obtained at different stages of the purification were assayed by phosphorolysis of polyadenylic acid (poly A) or 32P-orthophosphate exchange with the S’diphosphates of adenosine, uridine,...
متن کاملCharacterization of polynucleotide phosphorylase mutants of Escherichia coli.
Three polynucleotide phosphorylase mutations, isolated in heavily mutagenized Escherichia coli strains Q7, Q13, and Q27, were characterized after their transfer by P1 transduction to nearly isogenic strains which lack ribonuclease I. Each strain has a different altered form of polynucleotide phosphorylase. One enzyme exhibited sharply reduced activity under all conditions tested. A second had r...
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ژورنال
عنوان ژورنال: European Journal of Biochemistry
سال: 1970
ISSN: 0014-2956,1432-1033
DOI: 10.1111/j.1432-1033.1970.tb00281.x