Overview:
Defensins are a large family of peptides of which two groups exist in mammals: alpha defensins and beta defensins - which are distinguishable by the spacing and connectivity of the conserved cysteine residues within the mature peptides. It is thought that the function of defensins in the eradication of pathogens from the host system is to insert themselves into the bacterial membrane under the influence of membrane potential, in doing so forms channels which lead to leakage of cytoplasmic molecules and cell death. Unlike hBD-1, this second peptide, human beta-defensin-2 (hBD-2), is regulated at a transcriptional level in response to contact with microorganisms, and is highly effective in killing the gram negative bacteria. Its expression is also upregulated by the cytokine tumor necrosis factor-alpha.
Gene Aliases:
Beta-defensin 4A, BD-2, hBD-2, Defensin, beta 2, Skin-antimicrobial peptide 1, SAP1, DEFB102, DEFB2, DEFB4.
Genbank Number:
O15263
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我在做5RACE,选用TaKaRa公司的RNA反转录酶(RNaseH-),不知道这个酶好不好,有什么需要注意的。
没有序列识别的功能,他就是简单的催化相邻DNA链的5-P末端和3'-OH末端以磷酸二酯键结合的反应,需ATP作辅酶。 不仅可以催化粘性末端之间或平滑末端之间的DNA的连接,也催化DNA与RNA之间以及少数RNA之间的连接。
反转录酶(Reversetranscripatase)是以RNA为模板指导三磷酸脱氧核苷酸合成互补DNA(cDNA)的酶。哺乳类C型病毒的反转录酶和鼠类B型病毒的反转录酶都是一条多肽链。鸟类RNA病毒的反转录酶则由两上亚基结构。真核生物中也都分离出具有不同结构的反转录酶。

