Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The variable hydrophobic nature of proteins allows their separation through differential hydrophobic surface interactions. From these observations two modes of protein chromatography have been developed, hydrophobic-interaction chromatography (HIC) and reversed-phase chromatography (RPC). Selectivity of the HIC column can be easily manipulated by changing mobile phase variables. Protein retention was increased by decreasing the pH from neutrality or by using a salt with a greater "salting-out" ability. In addition, selectivity can be altered through chemical modification of the matrix surface. Protein retention and resolution decreased concomitantly with matrix ligand density. There were several major differences in HIC and RPC selectivity. Hydrophilic proteins such as cytochrome c and myoglobin were weakly retained on the HIC column but strongly retained on the RPC column. In contrast, a hydrophobic protein such as beta-glucosidase was strongly retained on the HIC column and only weakly retained on the RPC column. Other proteins were retained equally by RPC and HIC columns. Load capacity on the HIC column was determined by plotting resolution as a function of protein load. Resolution decreased significantly after 7.5 mg of total protein had been loaded onto the column per cm3 of column material. Samples of lactic dehydrogenase and alpha-chymotrypsin ranging in size from 10-200 micrograms were recovered from an HIC column with greater than 86% enzymatic activity in all cases. The recovery of enzymatic activity of alpha-chymotrypsin ranged from 55-91%, while none of the activity of beta-glucosidase was recovered from the RPC column.
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PMID:Comparison of hydrophobic-interaction and reversed-phase chromatography of proteins. 653 Apr 30

Analysis of insoluble complexes between tetragalloylglucose and proteins following a series of successive washes with buffer indicated (1) heterogeneity of binding between galloylglucose and protein and (2) irreversible denaturation of protein during interaction with galloylglucose. Relatively large amounts of tetragalloylglucose were removed by initial washes, indicating weak, low affinity binding, whereas smaller amounts removed by subsequent washes suggest bonds with a higher affinity. Although the maximum number of bindings sites, calculated per 10,000 M(r) of protein, was similar for BSA, myoglobin and lysozyme, the proportion of these sites that appeared to have high affinity, varied from 8 to 29%. The low proportion of strongly binding sites in lysozyme explains its relatively low tannin-complexing ability. Solubility decrease in protein during successive washing and decrease in the beta-glucosidase activity indicate that irreversible denaturation of protein occurs, which progresses with an increase in the incubation time with galloylglucose and galloylglucose/protein molar ratio in the mixture. Relative affinity of galloylglucose is directly related to the ability to cause irreversible denaturation.
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PMID:Binding nature and denaturation of protein during interaction with galloylglucose. 933 25