Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new method of formation of noncovalent complexes between poly(ethylene glycol) (PEG) and proteins (alpha-chymotrypsin (ChT), lysozyme, bovine serum albumin) under high pressure has been developed. The existence of polymer in complexes was proved using 3H-labeled PEG. Complexes between PEG and ChT were studied in detail. It was shown that the composition of complexes (the number of polymer chains per ChT molecule) depends on the molecular mass of PEG and decreases with the increase of molecular mass from 300 to 4000. At the same time, the portion of the protein (wt. %) in complexes does not depend on the molecular mass of incorporated PEG and corresponds to approximately 70 wt. %. It was shown that kinetic constants for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester and azocasein catalyzed by the PEG-ChT complexes are identical to the corresponding values for the native ChT. The conformational properties of ChT in complexes were studied by circular dichroism. It was shown that the enzyme in complexes fully retains its secondary structure. The estimation of steric availability of PEG polymer chains in complexes was evaluated by the complexation with alpha-cyclodextrin (CyD). It was shown that in contrast to free PEG, only part (approximately 10%) of PEG polymer chains in PEG--ChT complexes participate in the complexation with CyD. Hence, the complexation of PEG with ChT proceeds by means of multipoint interaction with surface groups of the protein globule in a region far from the active site of the enzyme and results in the significant decrease in the mobility of polymer chains.
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PMID:Noncovalent complexes between poly(ethylene glycol) and proteins. 986 73

A new method of preparation of noncovalent complexes between poly(ethylene glycol) (PEG) and proteins (alpha-chymotrypsin (ChT), lysozyme, bovine serum albumine) under high pressure has been developed. The involvement of polymer in the complexes was proved using (3)H-labeled PEG. The composition of the complexes (the number of polymer chains per one ChT molecule) depends on the molecular mass of PEG and decreases with the increase in molecular mass from 300 to 4000, whereas the portion of the protein (wt %) in complexes does not depend on the molecular mass of incorporated PEG and corresponds to approximately 70 wt %. The kinetic constants for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester and azocasein catalyzed by the PEG-ChT complexes are identical with the corresponding values for the native ChT. According to the data obtained by the method of circular dichroism, the enzyme in the complexes fully retains its secondary structure. The steric availability of PEG polymer chains in the complexes was evaluated by their complexation with alpha-cyclodextrin (CyD) or polymer derivatives of beta-CyD modified with PEG (PEG-beta-CyD). In contrast to free PEG, only part of PEG polymer chains ( approximately 10%) interact with alpha-CyD. Thus, the complexation of PEG with ChT proceeds by means of multipoint interaction with surface groups of the protein globule located far from the active site and results in the sufficient decrease in the availability of polymer chains. The complexes between PEG chains in PEG-protein adducts and PEG-beta-CyD may be considered as a novel type of dendritic structures.
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PMID:Noncovalent adducts of poly(ethylene glycols) with proteins. 1063 81

We report a kinetics study on hen egg white lysozyme's (HEWL) inhibitory effect on mushroom tyrosinase catalysis of 3-(3,4-dihydroxyphenyl)-L-alanine (L-DOPA) or L-tyrosine. For the first time, we demonstrate HEWL as a robust inhibitor against mushroom tyrosinase in catalysis of both substrates. The kinetics pattern matches a mixed (mostly non-competitive) partial inhibition. Ki and ID50 value of HEWL are more than 20-fold lower than that of kojic acid, a well-known chemical inhibitor of mushroom tyrosinase. Ki, alpha value and beta value, are almost identical in both experiments (L-DOPA and L-tyrosine as substrates, respectively), which suggests this common inhibition mechanism affects both steps. The inhibitory effect increases as both proteins were mixed and pre-incubated for less than 1 h. HEWL-depletion only removed about half of the inhibitory effect. Here we propose a novel function of HEWL, which combines the reversible inhibition and the irreversible inactivation toward mushroom tyrosinase. Discovery of HEWL as an inhibitor to mushroom tyrosinase catalysis may be commercially valuable in the food, medical and cosmetic industries.
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PMID:Hen egg white lysozyme as an inhibitor of mushroom tyrosinase. 1651 93


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