Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteinase K-treatment of red blood cells either diminished or abolished the antigenic activities of glycophorin A and glycophorin B, and revealed the presence of a cryptic antigen that was recognized by antibody naturally existing in the autoplasma. About ninety five percent of all healthy persons have this autoantibody belonging to the IgM classification, whose titer ranges from 2 to 32. The activity of this autoantibody was absorbed by histidine and glutaminic acid. We were able to isolate this autoantibody from the plasma by means of an alkaline elution method and the autoantibody did not agglutinate chymotrypsin-treated red blood cells and red blood cells treated with chymotrypsin, following proteinase K-treatment. These results indicate that after proteinase K-treatment this autoantibody may not have an affinity for glycolipids, but for proteins digested by chymotrypsin.
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PMID:Blood group antigens transformed by proteinase K-treatment and the discovery of a natural autoantibody of these treated red blood cells. 223 30

Invasion of the merozoite form of Plasmodium falciparum into human erythrocytes involves multiple receptor-ligand interactions. The EBA175 protein of P. falciparum has been shown to be the ligand that binds to a sialic acid-dependent site on glycophorin A. We have identified a novel P. falciparum ligand, termed erythrocyte-binding antigen 140 (EBA140), that shares structural features and homology with EBA175. Subcellular localization of EBA140 suggests that it is located in the micronemes, the same localization as EBA175. EBA140 binds to a sialic acid-dependent receptor on the surface of human erythrocytes. Binding of EBA140 to this erythrocyte receptor is sensitive to neuraminidase and resistant to trypsin, proteinase K and pronase. The protease-resistant properties of the erythrocyte receptor suggests that it is not glycophorin A or C. Additionally, analysis of mutant erythrocytes from humans has shown that EBA140 does not bind glycophorin B. Interestingly, we have identified a parasite line that lacks the eba140 gene, suggesting that this protein is not essential for in vitro invasion. These results suggest that EBA140 may be involved in merozoite invasion using a sialic acid-dependent receptor on human erythrocytes.
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PMID:A novel ligand from Plasmodium falciparum that binds to a sialic acid-containing receptor on the surface of human erythrocytes. 1145 99