Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.8 (polynucleotide phosphorylase)
 723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The oligoribonucleotide, A-A-A-C-U-U-U-Gp, constituting a segment of RNA bacteriophage Qbeta coat protein gene was efficiently synthesized at a milligram scale by a combination of enzymatic methods using bacteriophage T4 RNA ligase and the thermophilic polynucleotide phosphorylase. A-A-A-Cp was synthesized from A-A-A and pCp by the newly developed mononucleotide addition method using T4 RNA ligase in a yield of 83%, followed by dephosphorylation with bacterial alkaline phosphatase to obtain A-A-A-C. pU-U-U-Gp was synthesized from pU-U-U and GDP by the simultaneous action of polynucleotide phosphorylase and RNase T1 in a yield of 32%. finally, the two oligonucleotides (A-A-A-C and pU-U-U-Gp) were ligated with T4 RNA ligase and the octanucleotide, A-A-A-C-U-U-U-Gp, was obtained in a yield of 85%.
 ...
PMID:Enzymatic synthesis of a segment of bacteriophage Qbeta coat protein gene. 41 26

A number of "surface" enzymes of Escherichia coli (i.e., among those selectively released by osmotic shock) all displayed higher specific activities in extracts of minicells than in extracts of typical rod forms; these enzymes included alkaline phosphatase, cyclic phosphodiesterase, acid hexose monophosphatase, 5'-nucleotidase, and ribonuclease I. In addition, alkaline phosphatase, cyclic phosphodiesterase, and acid hexose monophosphatase were cytochemically localized to regions of minicell periplasm that resembled reactive polar enlargements of the periplasm in rod forms. In contrast, a number of "internal" cytoplasmic enzymes (inorganic pyrophosphatase, beta-galactosidase, glutamine synthetase, polynucleotide phosphorylase, and ribonuclease II) showed elevated or similar specific activities in extracts of rod forms versus extracts of minicells. A specific heat-labile inhibitor for 5'-nucleotidase, known to occur in the cytoplasm, also showed no enrichment in minicells. These findings indicate that the "surface" enzymes are segregated in vivo into the terminal minicell buds, possibly because these enzymes are concentrated in the polar enlargements of the periplasm in typical rod forms.
 ...
PMID:Biochemical and cytochemical evidence for the polar concentration of periplasmic enzymes in a "minicell" strain of Escherichia coli. 431 25

An enzyme, purified 300-fold from Escherichia coli infected with bacteriophage T4, catalyzes the conversion of 5'-termini of polyribonucleotides to internal phosphodiester bonds. The reaction requires ATP and Mg(++). For every 5'-(32)P terminus rendered resistant to alkaline phosphatase, an equal amount of AMP and PPi are formed. Various polyribonucleotides are substrates in the reaction; to date, the best substrate is [5'-(32)P]polyriboadenylate. With the latter substrate, no evidence of intermolecular reaction was obtained. However, the 5'-(32)P termini of poly(A) rendered resistant to alkaline phosphatase are also resistant to attack by RNase II, polynucleotide phosphorylase, and low concentrations of venom phosphodiesterase. Since the product formed with poly(A) lacks 3'-hydroxyl ends, as measured with these exonucleases, the enzyme appears to convert linear molecules of polyriboadenylate to a circular form by the intramolecular covalent linkage of the 5'-phosphate end to the 3'-hydroxyl terminus.
 ...
PMID:Purification and properties of bacteriophage T4-induced RNA ligase. 434 72

We describe a method for obtaining radioactive fingerprints from nonradioactive ribonucleic acid. Fragments derived by T1 ribonuclease digestion of RNA are dephosphorylated with bacterial alkaline phosphatase. When these fragments are used as primers for the reaction of primer dependent polynucleotide phosphorylase with [alpha-(32)P]GDP in the presence of T1 ribonuclease the 3'-hydroxyl group of each fragment becomes phosphorylated. The degree of phosphorylation is reasonably uniform. The method has been applied to T1 ribonuclease digests of Escherichia coli tRNA(Met) (f); the oligonucleotides were further analyzed by spleen phosphodiesterase digestion. In a similar manner fingerprints of pancreatic ribonuclease digests of RNA can be obtained, when [alpha-(32)P]UDP, polynucleotide phosphorylase and pancreatic ribonuclease are used.
 ...
PMID:Fingerprinting nonradioactive ribonucleic acid with the aid of polynucleotide phosphorylase. 1079 69

1. By digitonin lysis of penicillin spheroplasts of Escherichia coli a particulate fraction P(1) was previously obtained that supported the sustained synthesis of alkaline phosphatase when supplied with amino acids, nucleotide triphosphates and other cofactors. This P(1) fraction, when subjected to mild ultrasonic treatment in the presence of sucrose and Mg(2+), yielded the P(1)(S) fraction, consisting of integrated particulate subcellular particles containing DNA and RNA. 2. The P(1)(S) fraction from E. coli K10 wild type (R(+) (1)R(+) (2)P(+)) grown under repressed conditions supported the immediate synthesis of alkaline phosphatase in vitro. The synthesis occurred in phases. The first was followed by a lag, and then there was a linear rapid phase that continued for at least 3hr. Actinomycin D inhibited the appearance of the second phase. It was concluded that the particles are programmed to synthesize enzyme even when prepared from repressed cells, and therefore that synthesis of the specific messenger RNA for alkaline phosphatase in vivo was not inhibited when the bacteria were grown in an excess of inorganic phosphate. 3. Phosphate inhibited synthesis of enzyme to the same extent with the P(1)(S) fractions of two constitutive strains as with the P(1)(S) fraction of the wild-type strain. 4. Inorganic phosphate inhibited amino acid incorporation with the P(1)(S) fraction and also inhibited enzyme synthesis in vitro. The effect on amino acid incorporation could be partially overcome by adding Mn(2+) to the incubation mixtures. However, Mn(2+) inhibited the synthesis of alkaline phosphatase. Also, inhibition of the incorporation of [(32)P]CTP into RNA was overcome by Mn(2+). The effect of phosphate on amino acid uptake was most probably due to a phosphorolysis of RNA by polynucleotide phosphorylase, also present in the P(1)(S) fraction. This phosphorolysis may be responsible for the instability of messenger RNA in vitro and in vivo. 5. Phosphate also specifically inhibited the formation of alkaline phosphatase, since it did not affect markedly the induced formation of beta-galactosidase by the same P(1)(S) fraction. The specific effect is attributed to the prevention of formation of the enzymically active dimer from precursors, a Zn(2+)-dependent reaction. It is suggested that the repression of the synthesis of alkaline phosphatase in vivo in the wild-type strain was the sum of these two effects.
 ...
PMID:THE BIOSYNTHESIS OF ALKALINE PHOSPHATASE WITH A PARTICULATE FRACTION OF ESCHERICHIA COLI. 1433 60