Kinetic analysis of the interaction of alkyl glycosides with two human β-glucosidases
| Autor: | V Gopalan, Robert H. Glew, M Claeyssens, L B Daniels |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Stereochemistry
Fluorescence spectrometry Phosphatidylserines Biochemistry Cytosol Humans Glycosides Binding site Molecular Biology Alkyl chemistry.chemical_classification Binding Sites biology beta-Glucosidase Psychosine Active site Cell Biology Kinetics Enzyme Liver chemistry Enzyme inhibitor biology.protein Glucosylceramidase Glucocerebrosidase Glucosidases Research Article |
| Zdroj: | Biochemical Journal. 262:541-548 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | This paper addresses the similarities and differences in the topology of the catalytic centres of human liver cytosolic beta-glucosidase and placental lysosomal glucocerebrosidase, and utilizes well-documented reversible active-site-directed inhibitors. This comparative kinetic study was performed mainly to decipher the chemical and structural nature of the active site of the cytosolic beta-glucosidase, whose physiological function is unknown. Specifically, analysis of the effects of a family of alkyl beta-glucosides consistently displayed 100-250-fold lower inhibition constants with the cytosolic broad-specificity beta-glucosidase compared with the placental glucocerebrosidase; for example, with octyl beta-D-glucoside the Ki values were 10 microM and 1490 microM for the cytosolic and lysosomal beta-glucosidases respectively. Furthermore the higher affinity of the cytosolic beta-glucosidase than glucocerebrosidase for the amphipathic alkyl beta-D-glucosides was validated by the greater increase in the free energy of binding with increasing alkyl chain length [delta delta G0 (K,)/CH2: lysosomal enzyme, 2.01 kJ/mol (480 cal/mol); cytosolic enzyme, 3.05 kJ/mol (730 cal/mol)]. The implications of the presence of highly non-polar domains in the active site of the cytosolic beta-glucosidase are discussed with regard to its potential physiological substrates. |
| Databáze: | OpenAIRE |
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