Biomaterial Database

Glutathione activation of a cysteine proteinase from Schistosoma mansoni. 1987

C L Chappell, and M H Dresden, and D W Walters

A cysteine proteinase isolated from Schistosoma mansoni adults requires reduction by thiols for activation. The proteinase is located in the parasite digestive tract where it degrades hemoglobin released from host red blood cells. Reduced glutathione (GSH) has been shown to be effective in activation. Total glutathione concentration and the GSH/oxidized glutathione (GSSG) ratio were measured in whole blood lysate (3.2 mM, 284), serum (24 microM, 9.8) and material collected from the parasite digestive tract (4.2 mM, 137). The ratio of GSH/GSSG at which the enzyme displays half-maximal activity (Kox) is 1.0. Proteinase activation as a function of glutathione concentration and time was determined. The first-order reaction yielded a half-time of activation of 13 min at 5 mM. The second-order rate constant was 12.7 M-1 X min-1. The function of the proteinase and its possible regulation by glutathione activation are discussed.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010450	Endopeptidases	A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.	Endopeptidase,Peptide Peptidohydrolases
D003546	Cysteine Endopeptidases	ENDOPEPTIDASES which have a cysteine involved in the catalytic process. This group of enzymes is inactivated by CYSTEINE PROTEINASE INHIBITORS such as CYSTATINS and SULFHYDRYL REAGENTS.
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012550	Schistosoma mansoni	A species of trematode blood flukes of the family Schistosomatidae. It is common in the Nile delta. The intermediate host is the planorbid snail. This parasite causes schistosomiasis mansoni and intestinal bilharziasis.	Schistosoma mansonus,mansonus, Schistosoma
D012555	Schistosomiasis mansoni	Schistosomiasis caused by Schistosoma mansoni. It is endemic in Africa, the Middle East, South America, and the Caribbean and affects mainly the bowel, spleen, and liver.	Schistosomiasis, Intestinal,Schistosoma mansoni Infection,Infection, Schistosoma mansoni,Infections, Schistosoma mansoni,Intestinal Schistosomiases,Intestinal Schistosomiasis,Schistosoma mansoni Infections,Schistosomiases, Intestinal
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor