tioofpolysaccharide,polyetheleneglycol,andprotein-crowdingagentsontherefoldingofglucose-6-phohatedehydrogenase(g6pdh)andproteindisulfideisomerasehavebeenexamined.byincreasingconcentrationduringrefolding,thereactivationyieldsofthetwoproteidecreasedwiththeformationofsolubleaggregates.inthepresenceofhighconcentratioofcrowdingagentsthereactivationyieldsremaincotantbutwithdecreasedrefoldingrates.therefoldingofg6pdhchangedfrommonophasictobiphasicfirst-orderreactiointhepresenceofcrowdingagents,andtheamplitudeofthenewslowphaseincreaseswithincreasingconcentratioofcrowdingagents.themolecularchaperonegroelaiststherefoldingofg6pdhwithmarkedincreasedreactivationyieldandreversestherefoldingkineticsfrombiphasebacktomonophaseandacceleratestherefoldingproce.theresultsdilaythecomplexityandthediversityofeffectsofmacromolecularcrowdingonboththethermodynamicsandkineticsofproteinfolding.
metalregulationofmetallothioneinparticipationinredoxreactio.likeglutathioneordithiothreitol,metallothioneineffectstheformationofpancreaticribonucleaseafromitss-sulfonatedderivativecatalyzedbyproteindisulfideisomerase.edtaincreasestheyieldofribonucleaseaactivityrecoverywithmetallothioneinbutdoesnotaffectthereactionwithglutathioneordithiothreitol.edtaalsoincreasesthereactivityofthiolgrouinmetallothioneinwith5,5’-dithiobis-(2-nitrobenzoicacid)bychelationofzincio.itissuggestedthatthethiolgrouinmetallothioneinformapartofthepoolofcellularthiolsintheregulationofcellularredoxreactioandtheiravailabilityismodulatedbyzinc
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