Oligo -cellulose

C. Oligo- and Poly-nucleotides.—The stepwise enzymatic synthesis of internucleotide bonds has been reviewed. A number of polynucleotides containing modified bases have been synthesised " in the past year from nucleoside triphosphates with the aid of a polymerase enzyme, and the enzymatic synthesis of oligodeoxyribonucleotides using terminal deoxynucleotidyl transferase has been studied. Primer-independent polynucleotide phosphorylase from Micrococcus luteus has been attached to cellulose after the latter has been activated with cyanogen bromide. The preparation of insolubilized enzyme has enabled large quantities of synthetic polynucleotides to be made. The soluble enzyme has been used to prepare various modified polycytidylic acids. ... 

The mRNA is then isolated from this total cellular extract by affinity chromatography using oligo-dT-cellulose or poly(U)-sepharose. 

Most eukaryotic mRNA molecules have up to 250 adenine bases at their 3 end. These poly (A) tails can be used in the affinity chromatographic purification of mRNA from a total cellular RNA extract. Under high salt conditions, poly (A) will hybridize to oligo-dT-cellulose or poly(U)-sepharose. These materials are polymers of 10 to 20 deoxythymidine or uridine nucleotides covalently bound to a carbohydrate support. They bind mRNA containing poly (A) tails as short as 20 residues. rRNA and tRNA do not possess poly (A) sequences and will not bind. After washing the mRNA can be eluted with a low salt buffer. 

Endo-xylanases can be used industrially in two ways 1) to remove xylan from paper pulp to give purer cellulose, and 2) to convert xylan into D-xylose or xylo-oligo-sac jharides that can be further converted into useful materials. In the first case, at least, it is clear that the enzyme preparation should be free of cellulases, either by (hoosing, or producing by mutation, a strain that makes xylanases but not cellulases, or by separating the lattCT from the former after they are produced. In nearly all cases t tie use of a cellulase-firee strain is preferable. 

The mRNA for both Inhibitors I and II appeared to be typical of eukaryotic messengers that code for small proteins of 8-12,000 daltons having a poly(A) tail since both messengers bind specifically to ollgo(dT)-cellulose. There is no evidence of translatable messengers for the two inhibitors in the RNA fraction that did not bind to the oligo(dT) affinity resin (data not shown). 

Reactive prepolymers used as binders are produced by acrylation of oligomers, such as epoxy resins, urethanes, polyesters, silicones, oligo-buta-diene, melamine derivatives, cellulose, and starches. Prepolymers are the principal ingredients of coating formulations and largely determine the basic properties of the coating. Examples of industrially important acrylated prepolymers are in Table 5.9. 

Isolation of mRNA Using Oligo(dT)-Cellulose Matrix... 

Hydroxyethyl cellulose, three samples prepared from alkali cellulose and ethylene oxide (oxirane) to low degrees of molar substitution (MS) about 0.25, 0.4 and 0.6 moles of oxirane substituted per mole of glucose units (some oxirane units form substituted oligo-ethylene glycol chains). 

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