
Overview:
PKA C-gamma (PKAcγ) is a third isoform of the catalytic subunit of cAMP-dependent protein kinase. It was isolated from a human testis cDNA library and was clearly derived from a gene distinct from C-alpha and C-beta and showed tissue-specific expression. Whereas at the amino acid level C-alpha and C-beta showed 93% homology, C-gamma showed only about 80% homology to both C-alpha and C-beta (1). The PRKACG gene is intronless, contains remnants of a poly(A) tail, is flanked by direct repeats, and is co-linear with the PRKACA gene(2).
Gene Aliases:
KAPG; PKAr; cAPKr; PRKACG
Genbank Number:
NM_002732
References:
1.Beebe, S. J. et al: Molecular cloning of a tissue-specific protein kinase (C gamma) from human testis--representing a third isoform for the catalytic subunit of cAMP-dependent protein kinase. Molec. Endocr. 4: 465-475, 1990. 2.Reinton, N. et al: The gene encoding the C gamma catalytic subunit of cAMP-dependent protein kinase is a transcribed retroposon. Genomics 49: 290-297, 1998.
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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.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
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?
《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)

