Study of the type of RNA, degraded by polynucleotide phosphorylase in polyribosomal fraction of rat liver.
The type of RNA is studied, which is degraded by polynucleotide phosphorylase (PNPase) in the fraction of free ribosomes and ribosomes released from endoplasmic reticulum membranes with Triton X-100. Beta-32P labelled ADP, UDP, GDP and CDP are found among the degradation products of endogenous RNA of free and bound ribosomes in vitro in the presence of 32P-ortophosphate. An analysis of molar ratio of beta-32P-NDP isolated revealed that PNPase degrades RNA of GC type in both ribosome  fractions. The amount of PNPase-degraded RNA in bound ribosimes is 4-fold as high as that in free ribosomes under the same conditions. Analysis of stable 32P-RNA and rapidly labelled 32-P-dRNA, isolated from bound ribosomes after the incubation with and without inorganic phosphate, revealed that PNPase attacks the 28S fragment of RNA, which consists of about 370 nucleotides, and dRNA having a sedimentation coefficient less than 12S. The rate of dRNA degradation is considerably higher than that of rRNA. 5'-RNAase, hydrolysing synthetic homopolyribonucleotides to oligonucleotides with free 3'-OH terminal group, apparently participates, together with PNPase, in dRNA and rRNA degradation.
D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism; D011092:Polyethylene Glycols; D011117:Polyribonucleotide Nucleotidyltransferase; D011132:Polyribosomes / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism*; D051381:Rats; D012265:Ribonucleotides / Q000032:analysis
D012335:RNA, Ribosomal; D012265:Ribonucleotides; D011092:Polyethylene Glycols; D011117:Polyribonucleotide Nucleotidyltransferase
Issledovanie tipa RNA, razrushaemoĭ polinukleotidfosforilazoĭ v sostave poliribosomnoĭ fraktsii perceni krysy