常用融合蛋白切割位点PROTEASECOMPANYProteaseCaptureThrombinLeu-Val-Pro-Arg▼Gly-SerL-V-P-R▼G-SAmersham-Biosciences,Novagen,SIGMA,RocheBenzamidine-AgaroseFactorXaIle-Glu/Asp-Gly-Arg▼I-E/D-G-R▼Amersham-Biosciences,NewEnglandBiolabs,RocheBenzamidine-AgaroseEnterokinaseAsp-Asp-Asp-Asp-Lys▼D-D-D-D-K▼NewEnglandBiolabs,Novagen,RocheTrypsinInhibitor-AgaroseTEVproteaseGlu-Asn-Leu-Tyr-Phe-Gln▼GlyE-N-L-Y–F-Q▼GInvitrogen–LifeTechnologiesNi-NTA(6Hisrecomb.TEV)PreScissionLeu-Glu-Val-Leu-Phe-Gln▼Gly-ProL-E-V-L-F-Q▼G-PAmersham-BiosciencesGSTrapforGSTfusionenzymeTAGZymeHis-tagremovalbyExoproteolyticDigestionQiagenNi-NTA(6Hisrecomb.enzyme)InteinSitedithiothreitolcleavageNewEnglandBiolabsDTTeliminationbydialysisHRV3CProteaseLeu-Glu-Val-Leu-Phe-Gln▼Gly-ProNovagenNi-NTA(6Hisrecomb.enzyme)L-E-V-L-F-Q▼G-PSUMOProteaserecognizethetertiarystructureoftheubiquitin-like(UBL)protein,SUMOInvitrogen–LifeTechnologies,LifeSensorsNi-NTA(6Hisrecomb.enzyme)Kex-2-Arg-X-Lys/Arg-Arg▼Invitrogen–LifeTechnologies,Ni-NTA(6Hisrecomb.enzyme)KEX2对arg的专一性高,要求最重要。Arg前为lys效率最高,不切-Arg-lys,Pro影响KEX2切割羧肽酶羧肽酶B可以切割C端的Lys或Arg;羧肽酶A可以切割C端除了Lys、Arg、Pro的氨基酸,但如果倒数第二个氨基酸为Pro两种羧肽酶均不能作用1.胰蛋白酶属肽链内切酶,能把多肽链中Lys和Arg残基中的羧基侧切断。2.胰凝乳蛋白酶(亦称糜蛋白酶)属肽链内切酶,主要切断多肽链中的芳香族氨基酸(Phe、Trp、Tyr)残基的羧基一侧。3.羧肽酶(分A和B型),一般的题目中没有特别指明的话就是两种类型的功能都具备,可以从羧基端切除氨基酸(若羧基端的第1个或第2个氨基酸为Pro的则不能切除)。4.溴化氰处理,专一性的切割甲硫氨酸羧基端的肽键。