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)

We recently reported the development of three monoclonal antibodies (MoAbs) to biologically active human erythropoietin (Ep). In the present study, we investigated the epitope specificity of these three antibodies, as well as their reactivity with Eps derived from species other than man. All three antibodies reacted with the Ep polypeptide itself, rather than with its carbohydrate moieties. Moreover, all three antibodies recognized separate nonoverlapping epitopes. Further studies with reduced/alkylated Ep and with sodium dodecyl sulfate-denatured Ep suggested that two of the MoAbs, anti-Ep-2 and anti-Ep-16, were specific for conformational, nonlinear determinants on the Ep molecule, whereas the third MoAb, anti-Ep-26, appeared to recognize a linear epitope. However, anti-Ep-26 did not react with synthetic peptides representing the 26 amino-, the 99-129 mid-region, or the 10 carboxy-terminal residues of Ep, nor with trypsin-, chymotrypsin-, or V8 protease-digested fragments of Ep. When tested with Ep from different species, the neutralizing capabilities of the three MoAbs were clearly different. Comparing their effectiveness against baboon, ovine and murine Ep, antibody 2 was most effective at neutralizing baboon Ep, antibody 16 was most effective against murine Ep, and antibody 26 showed little reactivity with any of these nonhuman Eps. Because these various Eps readily stimulate across species barriers, it is likely that the receptor binding domain on Ep has remained relatively conserved during evolution. Our results therefore suggest that the neutralizing capacity of our three anti-Ep MoAbs is caused not by binding directly to the Ep receptor binding domain on Ep, but by binding to distant regions, causing conformational changes in Ep, or by binding to regions close to the binding site, steric hindrance.
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PMID:Immunochemical analysis of monoclonal antibodies to human erythropoietin. 168 48

When a single cell suspension of human adult marrow or fetal liver is treated briefly with trypsin, the number of erythroid bursts arising in culture is significantly increased. Erythroid colonies show less stimulation. The time to reach maximum burst number may also be shortened. The absolute increase in burst number is greater at higher concentrations of erythropoietin, suggesting a synergistic effect of trypsin treatment with that of erythropoietin. Trypsin also increases the size of the individual burst subunit. The trypsin effect is not limited to a given class of bursts as distinguished by subunit number. Other enzymes, pronase, chymotrypsin and phospholipase D, also increase burst number but to a lesser degree. The burst-stimulating effect of trypsin is enzymatic since it is completely prevented by DFP, a specific inhibitor of trypsin action.
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PMID:Trypsin enhances erythropoiesis in vitro. 740 Jun 71

Urine manipulation in sports drug testing has become a serious problem for doping control laboratories, and recent scandals in elite endurance sports have revealed the problem of urine manipulation presumably using proteases, which will impede the detection of drugs such as erythropoietin (EPO) or other peptide hormones. Using commonly accepted analytical strategies, a protocol was developed enabling the determination of elevated protease activities in doping control specimens followed by the visualization of protein degradation and identification of proteases such as chymotrypsin, trypsin and papain. Therefore, protease detection kits based on fluorescein isothiocyanate-labeled casein were employed, and protease concentrations greater than 15 microg/mL of urine entailed subsequent 1-dimensional gel electrophoretic visualization of urinary proteins. The presence of 20 microg of proteases per mL of urine caused a complete degradation of proteins usually observed in urinary matrices ("trace of burning"), while respective proteases were still detected in spiked urine samples after 10 days of storage at + 4 and - 20 degrees C. Identification of target proteases at respective molecular weights was accomplished using bottom-up sequencing approaches based on in-gel digestion of separated enzymes followed by capillary liquid chromatography--Orbitrap tandem mass spectrometry.
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PMID:Proteases in doping control analysis. 1752 83