Matches in SemOpenAlex for { <https://semopenalex.org/work/W2147557900> ?p ?o ?g. }
Showing items 1 to 94 of
94
with 100 items per page.
- W2147557900 endingPage "628" @default.
- W2147557900 startingPage "623" @default.
- W2147557900 abstract "The presteady-state kinetic parameters of the interaction of wild-type glucoamylase from Aspergillus niger (EC 3.2.1.3) with maltose were obtained and analysed in the pH range 3-7 with intervals of 0.25 pH units. In all cases the following three-step reaction scheme was found to apply. E+S ES1 ES2 E+P The general result of the analysis of the presteady-state kinetics is that glucoamylase G1 is affected by the protonation states of three groups, with pKa values of 2.7, 4.5 and 5.7 in the free enzyme and of 2.7, 4.75 and 6.5 in the first enzyme-substrate complex. The protonation of the group in the enzyme-substrate complex with a pKa 6.5 had no effect on k2 (1640 s-1) or k-2 (20±4 s-1), but resulted in a stronger enzyme-substrate interaction, due to a decrease of K1 from 40 to 6.3 mM. In other words, when the substrate is bound, the pKa of the acid group changes to increase the fraction of reactive enzyme. Since this pKa parallels that of the Michaelis complex, known from the pH-dependence of kcat, the group in question is most probably the catalytic acid Glu-179. Protonation of Glu-179 thus is of no importance in the second step, clearly indicating that this step represents a conformational change and not the actual hydrolysis step of the reaction. Protonation of the pKa = 4.75 group leads to a small decrease in k2 to 1090 s-1, and also to minor changes in K1. The group with pKa = 2.7 leads to a major decrease of k2, of which the limit may be zero, but shows no effect on K1. Thus no difference is seen between the pKa values of the free enzyme and of the first enzyme-substrate complex at low pH." @default.
- W2147557900 created "2016-06-24" @default.
- W2147557900 creator A5089839391 @default.
- W2147557900 date "2000-07-10" @default.
- W2147557900 modified "2023-09-27" @default.
- W2147557900 title "pH-dependence of the fast step of maltose hydrolysis catalysed by glucoamylase G1 from Aspergillus niger" @default.
- W2147557900 cites W1546595715 @default.
- W2147557900 cites W1983679593 @default.
- W2147557900 cites W1987250042 @default.
- W2147557900 cites W2006070046 @default.
- W2147557900 cites W2014041587 @default.
- W2147557900 cites W2033883812 @default.
- W2147557900 cites W2037775811 @default.
- W2147557900 cites W2061215285 @default.
- W2147557900 cites W2076683612 @default.
- W2147557900 cites W2081036420 @default.
- W2147557900 cites W2106121486 @default.
- W2147557900 cites W2121449154 @default.
- W2147557900 doi "https://doi.org/10.1042/bj3490623" @default.
- W2147557900 hasPubMedCentralId "https://www.ncbi.nlm.nih.gov/pmc/articles/1221186" @default.
- W2147557900 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/10880362" @default.
- W2147557900 hasPublicationYear "2000" @default.
- W2147557900 type Work @default.
- W2147557900 sameAs 2147557900 @default.
- W2147557900 citedByCount "7" @default.
- W2147557900 crossrefType "journal-article" @default.
- W2147557900 hasAuthorship W2147557900A5089839391 @default.
- W2147557900 hasConcept C111368507 @default.
- W2147557900 hasConcept C127313418 @default.
- W2147557900 hasConcept C145148216 @default.
- W2147557900 hasConcept C155647269 @default.
- W2147557900 hasConcept C161790260 @default.
- W2147557900 hasConcept C178790620 @default.
- W2147557900 hasConcept C181199279 @default.
- W2147557900 hasConcept C185592680 @default.
- W2147557900 hasConcept C2775960407 @default.
- W2147557900 hasConcept C2777289219 @default.
- W2147557900 hasConcept C2778197599 @default.
- W2147557900 hasConcept C30095370 @default.
- W2147557900 hasConcept C41183919 @default.
- W2147557900 hasConcept C55493867 @default.
- W2147557900 hasConcept C56856141 @default.
- W2147557900 hasConcept C71240020 @default.
- W2147557900 hasConcept C73969872 @default.
- W2147557900 hasConcept C94412978 @default.
- W2147557900 hasConceptScore W2147557900C111368507 @default.
- W2147557900 hasConceptScore W2147557900C127313418 @default.
- W2147557900 hasConceptScore W2147557900C145148216 @default.
- W2147557900 hasConceptScore W2147557900C155647269 @default.
- W2147557900 hasConceptScore W2147557900C161790260 @default.
- W2147557900 hasConceptScore W2147557900C178790620 @default.
- W2147557900 hasConceptScore W2147557900C181199279 @default.
- W2147557900 hasConceptScore W2147557900C185592680 @default.
- W2147557900 hasConceptScore W2147557900C2775960407 @default.
- W2147557900 hasConceptScore W2147557900C2777289219 @default.
- W2147557900 hasConceptScore W2147557900C2778197599 @default.
- W2147557900 hasConceptScore W2147557900C30095370 @default.
- W2147557900 hasConceptScore W2147557900C41183919 @default.
- W2147557900 hasConceptScore W2147557900C55493867 @default.
- W2147557900 hasConceptScore W2147557900C56856141 @default.
- W2147557900 hasConceptScore W2147557900C71240020 @default.
- W2147557900 hasConceptScore W2147557900C73969872 @default.
- W2147557900 hasConceptScore W2147557900C94412978 @default.
- W2147557900 hasIssue "2" @default.
- W2147557900 hasLocation W21475579001 @default.
- W2147557900 hasOpenAccess W2147557900 @default.
- W2147557900 hasPrimaryLocation W21475579001 @default.
- W2147557900 hasRelatedWork W1572157273 @default.
- W2147557900 hasRelatedWork W1580497766 @default.
- W2147557900 hasRelatedWork W1605572231 @default.
- W2147557900 hasRelatedWork W1981909980 @default.
- W2147557900 hasRelatedWork W1994382681 @default.
- W2147557900 hasRelatedWork W1996247489 @default.
- W2147557900 hasRelatedWork W2014744878 @default.
- W2147557900 hasRelatedWork W2016516840 @default.
- W2147557900 hasRelatedWork W2042324397 @default.
- W2147557900 hasRelatedWork W2046055901 @default.
- W2147557900 hasRelatedWork W2051858751 @default.
- W2147557900 hasRelatedWork W2055347330 @default.
- W2147557900 hasRelatedWork W2088636851 @default.
- W2147557900 hasRelatedWork W2155638944 @default.
- W2147557900 hasRelatedWork W2396627542 @default.
- W2147557900 hasRelatedWork W2399609219 @default.
- W2147557900 hasRelatedWork W2404644554 @default.
- W2147557900 hasRelatedWork W2409381769 @default.
- W2147557900 hasRelatedWork W303633486 @default.
- W2147557900 hasRelatedWork W33805383 @default.
- W2147557900 hasVolume "349" @default.
- W2147557900 isParatext "false" @default.
- W2147557900 isRetracted "false" @default.
- W2147557900 magId "2147557900" @default.
- W2147557900 workType "article" @default.