
Overview:
KAT2B (also known as PCAF) is a transcription cofactor with a histone acetyltransferase (HAT) activity. KAT2B protein associates with p300/CBP which is a large nuclear protein that bind to many sequence-specific factors that are involved in cell growth and/or differentiation, including c-jun and the adenoviral oncoprotein E1A (1). KAT2B has histone acetyl transferase activity with core histones and nucleosome core particles indicating that KAT2B plays a direct role in transcriptional regulation (2). PCAF functions as a coordinating factor in the regulation of HIF1A-mediated apoptosis and p53-dependent cell cycle progression.
Gene Aliases:
PCAF, CAF, P/CAF, GCN5L, GCN5L1
Genbank Number:
NM_003884
References:
1. Yang, X.-J. et.al: A p300/CBP-associated factor that competes with the adenoviral oncoprotein E1A. Nature 382: 319-324, 1996.2. Xu, W. et.al: Mammalian GCN5 and P/CAF acetyltransferases have homologous amino-terminal domains important for recognition of nucleosomal substrates. Molec. Cell. Biol. 18: 5659-5669, 1998.
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《血管紧张素转换酶抑制剂在心血管病中应用的中国专家共识》.PDF(242.69k)
1.对于抑制剂筛选工作(求ic50)是不是体系内酶与底物的量(底物应该是过量的)对实验结果影响不大。
2.如果要求算Km值,是不是需要知道反应产物的绝对量。反应时间文献上都是5分钟,反应速度就用反应产物量除以反应时间即可。
3.酶是进口分装的,规格5U,一次用不完,用PBS稀释后如何保存
谢谢
2、可逆抑制剂:包括
a、竞争性抑制剂,抑制剂与底物竞争性结合酶反应中心,使Km增大,而Vmax不变 b、非竞争性抑制剂,酶与抑制剂结合后还能与底物结合,但活性降低,使Vmax减小,而Km不变
c、反竞争性抑制剂,酶只能与底物结合后才能与抑制剂结合,Vmax与Km都减小
可逆抑制剂可用透析等方法除去,使酶恢复作用
1、测定酶比活力:底物需要过量么?测定时间多长?是否可以加入过量的底物,然后测定3min吸光度的增加值,从吸光度的变化值计算比活力。
2、在酶抑制剂筛选的过程中,是否需要保证底物过量?还是要水浴一定时间让反应完全?我看到文献说用终浓度为0.1μmol/mL的底物,终浓度为45U/ml的酶,我想问,假设总体积为1ml,那么终浓度为45U/ml的酶岂不是每分钟能转化4.8μmol的底物?那么0.1μmol/mL的底物不就几秒钟就反应完了?那么怎么测定初速度?

