Therearethreegeneralmethodstohydrolyzeproteinintoitscomposition,aminoacids.Thosemethodsareacidhydrolysis,alkalinehydrolysis,andenzymatichydrolysis.Strongacidisordinarilythemethodofchoice,andconstantboilinghydrochloricacid,6M,ismostfrequentlyused.ThereactionisusuallycarriedoutinevacuatedsealedtubesorunderN2(Nitrogen)at110Celciusdegreefor18to96hours.Undertheseconditions,peptidebondsarequantitativelyhydrolyzed(althoughrelativelylongperiodsarerequiredforthecompletehydrolysisofbondstovaline,leucine,andisoleucine).

　　Whilethecompletealkalinehydrolysisofproteins,isachievedwith2to4Msodiumhydroxideat100Celciusdegreefor4to8hours.Thisisoflimitedapplicationforroutineanalysis,becausecysteine,serine,threonine,andargininearedestroyedintheprocess,andpartialdestructionbydeaminationofotheraminoacidsoccurs.Thecompleteenzymatichydrolysisofproteinsisdifficult,becausemostenzymesattackonlyspecificpeptidebondsrapidly.

　　Mostproteinasesorproteaseswillnotcompletelybreaktheproteinstoaminoacids,insteadyouhavetocombineafewenzymesforthispurpose.Also,theenzyme(s)inthereactionwillbeleftinthereaction.