Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human sarcolectin is known as growth promoter and interferon-alpha/beta antagonist. Besides N-acetylneuraminic acid-dependent cell agglutination it also binds to a macrophage migration inhibitory factor (MIF). Several types of negatively charged carbohydrates interfere with this binding, indicating importance of a negatively charged cluster. Since human serum albumin that has very similar properties in gel electrophoretic analysis can also bind to this factor with a comparatively reduced extent, sarcolectin and albumin are compared biochemically and immunologically. Their peptide maps, generated by cleavage with cyanogen bromide and N-chlorosuccinimide, reveal no differences. The N-terminal sequences are identical up to the fourteenth position that have unequivocally been determined. Reactivities to anti-human serum albumin antibody that inhibits binding of sarcolectin to MIF are similar. Fractionation of human albumin by chromatography on hydroxyapatite yields a subfraction with increased specific activity, measured by extent of inhibition of sarcolectin-MIF interaction. It exhibits the same inhibitory capacity as a similarly derived subfraction from sarcolectin. Interestingly, rabbit and pig serum albumins are as active as human albumin to inhibit binding of sarcolectin to MIF, whereas hamster, mouse, horse and bovine albumin preparations were ineffective up to 2.5 mg/ml. Thus, sarcolectin appears to be a subfraction of human serum albumin whose functionally relevant molecular peculiarities are presently unknown. Neither treatment with organic solvents nor with lipases, but exposure to trypsin, chymotrypsin and pronase can impair sarcolectin's ability to bind MIF.
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PMID:Migration inhibitory factor-binding sarcolectin from human placenta is indistinguishable from a subfraction of human serum albumin. 798 Aug 71

The reverse staining, with imidazole-SDS-zinc, of PEG-linked proteins separated by SDS-PAGE was studied. Using model conjugates (interferon-alpha 2b (IFN-alpha2b) reacted with either a branched-chain (40,000) PEG (PEG2,40) or a linear monomethoxy PEG polymer (Mr of 12,000) and chromatographically purified monoPEG2,40-IFN-alpha2b), conventional small-format analytical gels (<1 mm thick) showed typical detection patterns (i.e., transparent, colorless bands clearly discernible against a zinc imidazolate-generated white gel background), in less than 20 min. Nonreacted (free) PEG was almost undetected, as expected. The reverse-stained PEGylated IFN-alpha2b patterns were qualitatively indistinguishable from those of parallel gels stained with iodine (I2). The LOD was estimated in the low nanogram range (e.g., at about 7 ng for mono- or bi-PEG2,40 IFN-alpha2b per lane on gradient (4-17%) gels). Also, this stain allowed the visualization of Coomassie blue-undetected PEG-IFN bands, and could be restained with I2. PEGylated species of lysozyme, a low-molecular-weight peptide, ovalbumin, and chymotrypsin were used to demonstrate the generality of this stain. We also show (i) how to counteract the adverse effect of some parameters (e.g., gel thickness above 1 mm, long gel length, low (e.g., 4-6%) acrylamide concentration) on the reverse staining process and (ii) that the properties of the reverse-stained PEGylated proteins remain unchanged, as judged by analyzing both the ion exchange chromatography-based positional isomer separation profile and enzyme-linked immunosorbent response of PEG-IFN recovered from gels. Consequently, this technique may be useful for the rapid analysis or the small-scale preparation of PEGylated proteins.
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PMID:Detection of PEGylated proteins in polyacrylamide gels by reverse staining with zinc and imidazole salts. 1844 61