因PCR是一种极敏感的扩增技术,易受污染的影响。小量的外源 DNA 污染可以与目的模板一块被扩增。当前一次扩增产物用来进行新的扩增反应时,会发生共同来源的污染,这称之为残余污染;从其他样品中纯化的 DNA 或克隆的 DNA 也会是污染源。卫生部已经明确规定,凡是用于临床检验的PCR试剂,都应该有
UNG酶技术,以防止污染。
FicoScript®Reverse Transcriptase(反转录酶) is an engineered version of M-MLV RT with reduced RNase H activity and increased thermal stability. The enzyme is purified to near homogeneity from E. coli containing the modified pol gene of Moloney Murine Leukemia Virus . The enzyme can be used to synthesize first-strand cDNA at temperatures up to 48°C, providing increased specificity, higher yields of cDNA, and more fulllength product than other reverse transcriptases. It can generate cDNA from 100 bp to >12 kb.It is suitable for qPCR. 1 、 Enzyme Storage Buffer: M-MLV Reverse Transcriptase is supplied in 20mM Tris-HCl (pH 7.5), 200mM NaCl, 0.1mM
EDTA, 1mM DTT, 0.01% Nonidet P-40 and 50% glycerol.
2 、 M-MLV Reverse Transcriptase 5X Reaction Buffer: When the M-MLV Reverse Transcriptase 5X Reaction Buffer supplied with this enzyme is diluted 1:5, it has a composition of 50mM Tris-HCl (pH 8.3 25°C ), 75mM KCl, 3mM MgCl 2 and 10mM DTT.
3 、 Source: Purified from an E. coli strain expressing a recombinant clone.
4 、 Storage Conditions: Store at – 20°C . Avoid exposure to frequent temperature changes.
5 、 Unit Definition: One unit is defined as the amount of enzyme required to catalyze the transfer of 1nmol of deoxynucleotide into acid-precipitable material in 10 minutes at 37°C . The reaction conditions are: 50mM Tris-HCl (pH 8.3), 7mM MgCl 2 ,
6 、 Usage Note: M-MLV Reverse Transcriptase is less processive than AMV Reverse Transcriptase, and therefore, more units of the M-MLV enzyme are required to generate the same amount of cDNA as in the AMV reaction. Thus, starting with 1μg of mRNA
in a first-strand cDNA synthesis, 200 units of the M-MLV enzyme are recommended as opposed to 25 units of the AMV enzyme.
1 、 AMV Reverse Transcriptase 5X Reaction Buffer: The AMV Reverse Transcriptase 5X Reaction Buffer supplied with this enzyme has a composition of 250mM Tris-HCl (pH 8.3 25°C ), 250mM KCl, 50mM MgCl 2 , 2.5mM spermidine and 50mM DTT.
2 、 Enzyme Storage Buffer: AMV Reverse Transcriptase (AMV-RT) is supplied in 200mM potassium phosphate (pH 7.2 4°C ), 0.2% Triton ? X-100, 2mM DTT and 50% glycerol.
3 、 Source: Purified from avian myeloblastosis virus particles.
4 、 Storage Conditions: Store at – 20°C . Avoid multiple freeze-thaw cycles and exposure to frequent temperature changes.
5 、 Unit Definition: One unit is defined as the amount of enzyme required to catalyze the transfer of 1nmol of deoxynucleotide into acid-precipitable material in 10 minutes at 37°C . The reaction conditions are: 50mM Tris-HCl (pH 8.3), 40mM KCl,
6 、 Usage Notes: The AMV Reverse Transcriptase 5X Reaction Buffer is intended for use in standard first-strand cDNA synthesis reactions. No deoxynucleotides are in the buffer; The formulation of AMV Reverse Transcriptase 5X Reaction Buffer is not compatible with M-MLV Reverse Transcriptase. Up to 10μl of an RT reaction containing AMV-RT and the supplied AMV Reverse Transcriptase Reaction Buffer can be added
to PCR amplification reactions that use TaqDNA Polymerase.