Unit Definition | One Weiss unit of T4 DNA Ligase converts 1 nmole of p32 from pyrophosphate into Norit-adsorbable material in 20 minutes at 37℃ in 33 mM Tris-acetate (pH 7.8), 66 mM potassium acetate, 10 mM magnesium acetate, 0.5 mM DTT, and 1 mM ATP. One Weiss unit equals approximately 200 cohesive- end ligation units. |
---|---|
Quality Control | T4 DNA Ligase is functionally tested in cloning assays and is free of detectable contaminating DNA exo- and endo-nuclease and RNase activities. |
Concentration | 1 Weiss unit/㎕ |
Storage Buffer | 50 mM Tris-HCl (pH 7.5), 0.1 M NaCl, 0.1 mM EDTA, 0.1% Triton X-100, and 1 mM DTT, 50% Glycerol |
10X Reaction buffer | composed of 400mM Tris-HCl, 100mM MgCl2, 100mM DTT, 5mM ATP (pH 7.8 at 25°C). |
Application | Cloning of restriction fragments |
Joining linkers and adapters to blunt-ended DNA |
T4 DNA Ligase is the most versatile and commonly used ligase for DNA cloning. This ATP-dependent enzyme covalently joins 5'-phosphates to 3'-hydroxy-lated termini at the blunt or compatible cohesive ends of double-stranded DNA fragments produced by restriction enzyme digestion or other enzymatic processes.
T4 DNA Ligase has no activity on single- stranded nucleic acids. Following a ligation reaction, T4 DNA Ligase may be inactivated by incubation at 65℃ for 10 minutes.
ebiomall.com
>
>
>
>
>
>
>
>
>
>
>
>
逆转录(reverse transcription)是以RNA为模板合成DNA的过程,即RNA指导下的DNA合成。是RNA病毒的复制形式,需逆转录酶的催化。艾滋病病毒(HIV)就是一种典型的逆转录病毒。
逆转录与反转录严格意义上来说没有什么区别,但是逆转录是RNA类病毒自主行为,在整合到宿主细胞内以RNA为模板形成DNA的过程;反转录是进行基因工程过程中,人为地提取出所需要的目的基因的信使RNA,并以之为模板人工合成DNA的过程。二者虽同为RNA→DNA的过程,但地点不同,相对性的来说,逆转录在体内,反转录在体外。