Proteasome Endopeptidase ComplexProtein StabilityProteasome InhibitorsEnzyme StabilityLeupeptinsDrug StabilityCysteine EndopeptidasesMultienzyme ComplexesProtein DenaturationProtein FoldingBoronic AcidsUbiquitinationCysteine Proteinase InhibitorsThermodynamicsPyrazinesProteolysisMolecular Sequence DataModels, MolecularMutationAmino Acid SequenceProteinsUbiquitinsRNA StabilityProtein BindingProtein ConformationProtein Structure, TertiaryProtease InhibitorsUbiquitin-Protein LigasesCell LineTemperatureCircular DichroismProtein Structure, SecondaryProtein Processing, Post-TranslationalPeptide HydrolasesCell Line, TumorAmino Acid SubstitutionMutagenesis, Site-DirectedUbiquitinProtein EngineeringGuanidineProtein UnfoldingAcetylcysteineKineticsHEK293 CellsRNA, MessengerPhosphorylationProtein SubunitsHalf-LifeRecombinant ProteinsHeLa CellsHot TemperatureSignal TransductionBase SequenceBinding SitesCalorimetry, Differential ScanningDNA-Binding ProteinsNuclear ProteinsApoptosisBlotting, WesternSaccharomyces cerevisiaeTranscription FactorsTranscription, GeneticPolyubiquitinTransfectionModels, BiologicalStructure-Activity RelationshipAmino Acid MotifsGene Expression RegulationRecombinant Fusion ProteinsMuramidaseUreaSaccharomyces cerevisiae ProteinsMutant ProteinsMutation, MissenseEndopeptidasesHydrogen BondingCOS CellsProtein TransportTumor Suppressor Protein p53Molecular ChaperonesImmunoprecipitationEscherichia coliSequence Homology, Amino AcidDown-RegulationHydrogen-Ion ConcentrationCells, CulturedCarrier ProteinsRNA, Small InterferingSolventsF-Box ProteinsModels, ChemicalCell Cycle ProteinsProto-Oncogene Proteins c-mdm2ImmunoblottingMultiprotein ComplexesOligopeptidesSequence AlignmentTransition TemperatureCell NucleusCrystallography, X-Ray