| Description | Inquire | Seals and prevents freezing of stopcocks and ground-glass joints in high-vacuum systems at pressures less than 10-6 mm Hg. Heat stable (?40 to 260 °C), low vapor pressure, and chemically resistant. Colorless. 5.3 oz. tube | Inquire | Reverse transcriptases are enzymes encoded in retroviruses viral genome. The enzyme is responsible for transcription of the viral RNA to produce a dsDNA that can be inserted into the host genome.Reverse transcriptases are multifunctional enzymes. These enzymes exhibit an RNA and DNA directed Reverse transcriptases are enzymes encoded in retroviruses viral genome. The enzyme is responsible for transcription of the viral RNA to produce a dsDNA that can be inserted into the host genome.Reverse transcriptases are multifunctional enzymes. These enzymes exhibit an RNA and DNA directed polymerase activity. In addition reverse transcriptases catalyze the degradation of RNA in an RNA-DNA hybrid. The exonucleolytic activity proceeds in a 5' ---> 3' direction. The RNA or DNA directed activity requires a template (RNA or DNA) and a primer. The following is a schematic illustration of the reaction:Unit definition: One unit incorporates 1 nanomole of tritiated dTMP into acid insoluble productsusing poly(A)•oligo(dT) 12-18 as the template-primer in 20 minutes at 37° C.ApplicationsHIV reverse transcriptase is used for research on the AIDS primer. However it can be substituted for AMV reverse transcriptase, which is mainly used to transcribe mRNA into double stranded cDNA, that can be inserted into prokaryotic vectors. The enzyme can also be used with either single stranded DNA or RNA templates to make probes for use in hybridization experiments. It can be used for labeling the termini of DNA fragments with protruding 5' termini. The enzyme can also be used to sequence DNAs by the dideoxy chain termination method of Sanger when the Klenow fragment of E. coli DNA polymerase I, or the T7 DNA polymerase yield unsatisfactory results.Reagents0.05 M Tris, pH 8.3, containing 0.008 M MgCl21 mg/ml polyadenylic acid in water (poly A)DNA primer:Oligo d(T)12-181 µ mole dTTP/mL stock solution[methyl-3H]-Thymidine 5'-triphosphate (3H-dTTP)dTTP-3H-dTTP working mix: Add 1-2 µL 3H-dTTP per mL of 100 nmol/mL dTTP in order to obtain 1 to 1.5 x 105 cpm/mL1% bovine serum albumin10% perchloric acid1% perchloric acidBuffer substrate reaction mixture: Prepare fresh, immediately before use:For each 1mL of reaction mixture required mix:0.7 mL Tris/HCl, pH 8.3, 0.008M MgCl20.3 mL 1 mg/mL poly(A) RNA template0.005 mL 0.02 mg/mL oligo d(T)12-18 DNA primer0.02mL 1% BSAEnzymedilute as needed wtih 0.05M Tris/HCl, pH 8.3, 0.008M MgCl2 containing 0.1 mg/mL (1%) BSAProcedurePipette into each tube as follows:Buffer substrate mix：0.1 mLdTTP-3H3-dTTP：0.1 mLEnzyme：5-10 µLIncubate 20 minutes at 37° C. Stop reaction by adding 1 ml 10% cold perchloric acid. Filter through 0.2µ manifold filters used with Millipore vacuum manifold. Wash four times using 2mL 1% cold perchloric acid/wash. Transfer filter to scintillation vials. Add 2mL Cellosolve (or 2-methoxyethanol) to dissolve filter. Filters become opaque upon addition of Cellosolve. Make sure filters are dissolved before proceeding. Add 10mL scintillation cocktail and count.Calculation... Read More | Ribonuclease T1 is an endoribonuclease, highly specific for the cleavage of RNA or deaminated RNA between guanosine 3'-phosphate residues (or inosine 3'-phosphate) and the 5'-OH residues of adjacent nucleotides with the formation of the corresponding intermediate 2', 3'-cyclic phosphates. It cleavesRibonuclease T1 is an endoribonuclease, highly specific for the cleavage of RNA or deaminated RNA between guanosine 3'-phosphate residues (or inosine 3'-phosphate) and the 5'-OH residues of adjacent nucleotides with the formation of the corresponding intermediate 2', 3'-cyclic phosphates. It cleaves single-stranded RNA releasing oligonucleotides from the guanosine 3'-phosphate termini. The enzyme has a molecular weight of 11 kDa. The optimum pH is 7.5. RNase T1 is inhibited by Ag+, Zn2+, Cu2+, and Hg2+ at 1 X 10-3 M. The stimulatory effects of both histidine and EDTA are attributed to chelation of contaminating inhibitor cations. The enzyme assay is essentially the method of Egami et al., Prog. in Nucleic Acid Res. and Molec. Biol., III, 59 (1964) based upon the release of acid soluble oligonucleotides following the digestion of yeast RNA.Ribonuclease T1 (RNase T1) from Aspergillus oryzae is used to digest denatured RNA prior to sequencing and is used for protein folding studies. ApplicationRibonuclease T1 has extensive applications in molecular cloning and DNA sequencing. Because of its specificity it has been a commonly used cleavage enzyme for the determination of structure, nearest neighbor frequencies, and RNA sequencing. The enzyme has further application in the preparation of nucleoside 2',3'-cyclic phosphates, the synthesis of oligonucleotides, and the removal of RNA from DNA preparations. The enzyme is also used as a non-mammalian source of RNase in various applications... Read More |