Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.1 (alcohol dehydrogenase)
 9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The caseins are major components of milk for most mammals and are secreted as large colloidal aggregates termed micelles. They have less ordered secondary and tertiary structures in comparison with typical globular proteins. In this work, beta-casein, a member of the casein family, has been demonstrated to exhibit chaperone-like activity, being able to suppress the thermal and chemical aggregation of such substrate proteins as insulin, lysozyme, alcohol dehydrogenase, and catalase by forming stable complexes with the denaturing substrate proteins. Meanwhile, beta-casein was found to not only prevent aggregation of the substrate proteins, but also solubilize the protein aggregates already formed. Data also show that beta-casein exhibits a higher chaperone-like activity than alpha-casein, likely due to the difference in the number of proline residues present and/or in the extent of exposed hydrophobic surfaces. The implications for their in vivo functions of the caseins, based on their exhibiting such in vitro chaperone-like activities, are discussed.
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PMID:Chaperone-like activity of beta-casein. 1577 87

Beta-casein (beta-CN) showing properties of intrinsically unstructured proteins (IUP) displays many similarities with molecular chaperones and shows anti-aggregation activity in vitro. Chaperone activities of bovine and camel beta-CN were studied using alcohol dehydrogenase (ADH) as a substrate. To obtain an adequate relevant information about the chaperone capacities of studied caseins, three different physical parameters including chaperone constant (k(c), microM(-1)), thermal aggregation constant (k(T), degrees C(-1)) and aggregation rate constant (k(t), min(-1)) were measured. Bovine beta-CN displays greater chaperone activity than camel beta-CN. Fluorescence studies of 8-anilino-1-naphthalenesulfonic acid (ANS) binding demonstrated that bovine beta-CN is doted with larger effective hydrophobic surfaces at all studied temperatures than camel beta-CN. Greater relative hydrophobicity of bovine beta-CN than camel beta-CN may be a factor responsible for stronger interactions of bovine beta-CN with the aggregation-prone pre denatured molecular species of the substrate ADH, which resulted in greater chaperone activity of bovine beta-CN.
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PMID:Chaperone activities of bovine and camel beta-caseins: Importance of their surface hydrophobicity in protection against alcohol dehydrogenase aggregation. 1833 1

As a member of intrinsically unstructured protein family, beta-casein (beta-CN) contains relatively high amount of prolyl residues, adopts noncompact and flexible structure and exhibits chaperone-like activity in vitro. Like many chaperones, native beta-CN does not contain cysteinyl residues and exhibits strong tendencies for self-association. The chaperone-like activities of three recombinant beta-CNs wild type (WT) beta-CN, C4 beta-CN (with cysteinyl residue in position 4) and C208 beta-CN (with cysteinyl residue in position 208), expressed and purified from E. coli, which, consequently, lack the phosphorylated residues, were examined and compared with that of native beta-CN using insulin and alcohol dehydrogenase as target/substrate proteins. The dimers (beta-CND) of C4-beta-CN and C208 beta-CN were also studied and their chaperone-like activities were compared with those of their monomeric forms. Lacking phosphorylation, WT beta-CN, C208 beta-CN, C4 beta-CN and C4 beta-CND exhibited significantly lower chaperone-like activities than native beta-CN. Dimerization of C208 beta-CN with two distal hydrophilic domains considerably improved its chaperone-like activity in comparison with its monomeric form. The obtained results demonstrate the significant role played by the polar contributions of phosphorylated residues and N-terminal hydrophilic domain as important functional elements in enhancing the chaperone-like activity of native beta-CN. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 623-632, 2009.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.
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PMID:Chaperone-like activities of different molecular forms of beta-casein. Importance of polarity of N-terminal hydrophilic domain. 1932 74

To elucidate the correlation of structural peculiarities of beta-casein and their chaperon-like activity the modified forms of the protein (with cysteinyl residues introduced in polypeptide chain) were investigated. The aggregation of native and recombinant beta-caseins was studied as well as their chaperon-like activity towards alcohol dehydrogenase thermal aggregation. It was shown that physico-chemical and chaperone-like properties ofdimeric and oligomeric forms ofbeta-casein (which formation is due to intermolecular disulfide bonds) differ significantly from monomeric forms. It was found that thermal stability of alcohol dehydrogenase depends on beta-casein concentration.
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PMID:[Chaperone-like activity of beta-casein and thermal stability of alcohol dehydrogenase]. 2279 26