Studies On Lectins Of Boletus,Russula And Analogues

Lectin is a class of proteins or glycoproteins that bind specifically to sugars,which can agglutinate cells or precipitate sugar complexes,and their presence can be attested by hemagglutination tests.Lectins not only exsist in plants and animals,but also widely found in macrofungi.At present,systematic screening for macrofungi coagulation activity is less.In this thesis,lectins were extracted from 67 kinds of wild mushrooms(Boletus,Russula,and their analogues)with PBS buffer,Tris-HCl buffer,normal saline and sterile water.The agglutinin with high agglutination activity and the best extraction buffer were selected by hemagglutination tests.Some extracted lectins with high agglutination activity were primary purified.and their physical and chemical characters were also analysed.The major results of the thesis are as follows:1.The extracts of Tylopilus balloui.Turbinellus floccosus and Ramaria indoyunnaniana with the four kinds of buffer didn't show agglutination activity.While,an army of wild mushrooms shown high agglutination activity such as B.subvelutipes.B.roseoflavus,B.speciosus,B.brunneissimus.B.umbriniporus,Porphyrellus nigropurpureus,Lactarius volemus,L.deliciosus,R.virescens,Inocybe brunnea,Cralerellus lutescens and so on.In the case of B.roseoflavus,its optimal extraction buffer was taken as normal saline and agglutination titer was 4096 at the ratio of 1:10.2.Lectin extracts from B.brurmeissimus,B.roseoflavus,B.subvelutipes,B.calopus,B.bicolor,R.Virescens and L.piperatus were purified by ammonium sulfate fractionation.Taking L.piperatus as an example,the crude protein shown high specific activity of 44.33 × 103 U/mg in the best ammonium sulfate saturation of 40%,purified 4.39 times than the crude extract of 10.10 × 103 U/mg.3.The thermostability and sugar inhibition tests of the lectins from B.bicolor,B.brunneissimus and B.subvelutipes demonstrated that they are thermostable and their agglutination activity was inhibited by specific sugars.Taking B.brunneissimus as an example,its agglutination activity was completely lost at 90 ? and was inhibited by N-acetylglucosamine,L-rhamnose and D-mannose.