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In vitro synthesis of polyribonucleotides
Author(s) -
Cherepak M. M.,
Hansen R. W.
Publication year - 1968
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260100309
Subject(s) - polynucleotide phosphorylase , ribonucleoside , polynucleotide , primer (cosmetics) , chemistry , substrate (aquarium) , polymerization , enzyme , ribonucleotide , polymerase , rna , stereochemistry , biochemistry , gtp' , rna polymerase , polymer , nucleotide , organic chemistry , biology , purine nucleoside phosphorylase , ecology , purine , gene
Polyribonucleotide: orthophosphate nucleotidyl transferase, commonly known as polynucleotide phosphorylase catalyzes the reversible polymerization of ribonucleoside diphosphates with the liberation of orthophosphate. The equilibrium constant is approximately 1.0. Although isolated from a variety of sources, the enzyme occurs essentially as two types: one which does not require a primer for reaction initiation and a second which does. A parallel study of an E. coli preparation representing the first type and an M. lysodeikticus preparation representing the second showed differences other than the primer requirement. Rates of polymerization were different as were the K m s. The E. coli preparation catalyzed the synthesis of polyguanylic acid while the M. lysodeikticus preparation did not although synthesis of hetoropolymers containing guanylic acid was catalyzed by the M. lysodeikticus enzyme. Use of repurified commercial substrates made the validity of some primer‐requirement experiments suspect. End group analysis of product polymers served only to raise questions concerning the reaction‐initiating compounds and the reaction mechanism. A study of hetero‐polymer synthesis showed not only that the rate of polymerization was different, from that of homopolymers but that uncompetitive inhibition rather than competitive inhibition occurred when two ribonucleoside diphosphates were present in the reaction mixture. Furthermore, the experiments showed a preferential uptake of one substrate over another and an “enrichment” which was constant. It has also been shown that RNA polymerase, a DNA‐RNA directed polymerase, can be used to synthesize polyribonucleotides if the appropriate template is provided.