Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P11021 (BiP)
 2,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The proteins of the postsynaptic density (PSD) fraction of cerebral cortex were resolved by two-dimensional electrophoresis (2DE) and more than 30 proteins identified by characteristic 2DE mobility, immunoblotting with specific antibodies, and N-terminal and peptide sequencing. The PSD fraction is enriched for spectrin, actin, tublin and microtubule associated protein II, myosin, enzymes of glycolysis, creatine kinase, elongation factor 1 alpha, and receptor protein. The three neurofilament proteins are detected but a 58-kDa protein is prominent and is, by peptide sequencing, the bovine homolog of the recently cloned 66-kDa neurofilament protein; in contrast to the latter, however, it is enriched in cerebrum compared with spinal cord. A 68-kDa protein is identified as a member of the hsp70/BiP family of proteins. A protein, designated dynamin, indicating its putative role as a microtubule motor, is identified as a major protein, is found, however, greatly enriched in the particulate fraction, and is significantly denaturant and detergent insoluble. A protein designated N-ethylmaleimide-sensitive factor is also detected. Thus, two proteins implicated in vesicular transport are present in the PSD fraction. Seven polyclonal antibodies were produced to 2DE separated and electroeluted proteins of the PSD and were identified by peptide sequence analysis and 2DE profile as the hsp70/BiP homologous protein, the novel neurofilament protein synapsin IIa, pyruvate kinase, dynamin, aconitase and an unknown contaminating protein, and a 115-kDa protein that by subcellular fractionation and immunoblotting is a diagnostic PSD molecule. In addition, peptide sequences are obtained for four additional higher molecular weight proteins of the PSD that are not related at the level of primary structure to any known proteins.
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PMID:The postsynaptic density: constituent and associated proteins characterized by electrophoresis, immunoblotting, and peptide sequencing. 162 37

It has been shown previously that CaBP2, the rat analog of the murine protein ERp72, and CaBP1, the rat analogue of the hamster protein P5, represent members of the protein disulfide isomerase (PDI) family and are able to catalyze the reduction of insulin in the presence of various reductants (Nguyen Van et al., 1993). We have now examined the abilities of CaBP2 and CaBP1 to catalyze the renaturation of denatured reduced model proteins. Both CaBP2 and CaBP1 catalyzed the reappearance of the biological activity of the denatured reduced Fab fragment of a monoclonal anti-human creatine phosphokinase antibody. The reaction rate was positively correlated with the amount of CaBP2 or CaBP1 and dependent on the GSH/GSSG ratio (maximum at GSH/GSSG = 1). Peptide prolyl-cis,trans-isomerase (PPI), which catalyzed some renaturation on its own, showed synergistic effects with PDI, CaBP2, and CaBP1. No synergistic effects could be observed when the combinations CaBP2 + PDI, CaBP1 + PDI, or CaBP2 + CaBP1 were tested. Variation of [Ca2+] between 0 and 1 mM did not have any effect on the rate or amount of renaturation catalyzed by CaBP2, CaBP1, or PDI, nor were these parameters affected by the simultaneous presence of BiP or grp94. Both CaBP2 and CaBP1 catalyzed also the renaturation of denatured reduced ribonuclease AIII in a way that depended on the amounts of CaBP2 or CaBP1 and on the redox potential of the redox system used (GSH/GSSG or CSH/CSSC). PPI alone had no effect on the rate of RNase AIII renaturation and did not significantly affect renaturation catalyzed by PDI, CaBP2, or CaBP1. PDI showed a moderate but significant synergism with CaBP2, and a strong synergism with CaBP1. The results indicate that both CaBP2 and CaBP1 can catalyze the formation of disulfide bonds and protein disulfide isomerization and may thus be involved in the folding of nascent proteins in the secretory pathway. This does not exclude the possibility of additional functions of these proteins in the pre-Golgi compartments.
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PMID:Effects of CaBP2, the rat analog of ERp72, and of CaBP1 on the refolding of denatured reduced proteins. Comparison with protein disulfide isomerase. 830 May 76

The Fab fragment of the murine monoclonal antibody, MAK33, directed against human creatine kinase of the muscle-type, was crystallized and the three-dimensional structure was determined to 2.9 A. The antigen-binding surface of MAK33 shows a convex overall shape typical for immunoglobulins binding large antigens. The structure allows us to analyze the environment of cis-prolyl-peptide bonds whose isomerization is of key importance in the folding process. These residues seem to be involved with not only domain stability but also seem to play a role in the association of heavy and light chains, reinforcing the importance of beta-strand recognition in antibody assembly. The structure also allows the localization of segments of primary sequence postulated to represent binding sites for the ER-specific chaperone BiP within the context of the entire Fab fragment. These sequences are found primarily in beta-strands that are necessary for interactions between the individual domains.
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PMID:The crystal structure of the fab fragment of the monoclonal antibody MAK33. Implications for folding and interaction with the chaperone bip. 1103 70