Evidence for beta-galactosidase catalyzed hydrolysis of paranitrophenyl-beta-D-galactopyranoside anchored in cyclodextrins.

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dc.contributor.authorJyothirmayi, Nen_US
dc.contributor.authorRamadoss, C Sen_US
dc.date.accessioned1993-08-01en_US
dc.date.accessioned2009-05-27T09:53:31Z
dc.date.available1993-08-01en_US
dc.date.available2009-05-27T09:53:31Z
dc.date.issued1993-08-01en_US
dc.description.abstractThe absorption maximum of p-nitrophenol upon mixing with molar equivalents of alpha-cyclodextrin (alpha-CD) or hydroxypropyl-beta-cyclodextrin (HPB) showed nearly 5 nm shift to the longer wavelength region, indicative of complex formation, while beta-cyclodextrin (beta-CD), gamma-cyclodextrin (gamma-CD) and hydroxyethyl-beta-cyclodextrin (HEB) produced only a marginal shift of about 1-2 nm, suggestive of a weaker interaction. It has been shown by circular dichroism spectral studies that the aglycon part of p-nitrophenyl-beta-D-glycoside (PNPG) is also encapsulated by alpha-cyclodextrin. The encapsulated form of PNPG could be hydrolyzed by beta-galactosidase, the temperature and pH-optima for hydrolysis of anchored substrates being essentially identical to that of free substrate. However, small but consistent increase in Km values were obtained for alpha-cyclodextrin-, HEB- and HPB-anchored substrates. The kcat values also registered an increase for the HEB- and HPB-anchored substrates. However, there was no increase in kinetic efficiency (kcat/Km) of enzyme. The inhibition noted at higher concentrations of HEB- and gamma-cyclodextrin-anchored PNPG but not with o-nitrophenyl-beta-D-galactoside (ONPG)-cyclodextrin mixture suggests that PNPG-cyclodextrin complexes were responsible for the inhibition. Taken together, these results suggest that the enzyme catalyses the hydrolysis of anchored substrates.en_US
dc.description.affiliationDepartment of Food Chemistry, Central Food Technological Research Institute, Mysore, India.en_US
dc.identifier.citationJyothirmayi N, Ramadoss CS. Evidence for beta-galactosidase catalyzed hydrolysis of paranitrophenyl-beta-D-galactopyranoside anchored in cyclodextrins. Indian Journal of Biochemistry & Biophysics. 1993 Aug; 30(4): 218-23en_US
dc.identifier.urihttps://imsear.searo.who.int/handle/123456789/28870
dc.language.isoengen_US
dc.source.urihttps://https://www.niscair.res.in/ScienceCommunication/ResearchJournals/rejour/ijbb/ijbb0.aspen_US
dc.subject.meshCyclodextrins --pharmacologyen_US
dc.subject.meshEscherichia coli --enzymologyen_US
dc.subject.meshHydrogen-Ion Concentrationen_US
dc.subject.meshHydrolysisen_US
dc.subject.meshKineticsen_US
dc.subject.meshNitrophenylgalactosides --metabolismen_US
dc.subject.meshThermodynamicsen_US
dc.subject.meshbeta-Galactosidase --metabolismen_US
dc.titleEvidence for beta-galactosidase catalyzed hydrolysis of paranitrophenyl-beta-D-galactopyranoside anchored in cyclodextrins.en_US
dc.typeJournal Articleen_US
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