Biomaterial Database

Comparative studies on calotropins DI and DII from the latex of Calotropis gigantea. 1984

A Sengupta, and D Bhattacharya, and G Pal, and N K Sinha

Autodigestion of two cysteine proteinases, calotropins DI and DII isolated from the latex of Calotropis gigantea, has been studied at pH 7.5 and 37 degrees C in the presence of an activating agent. Calotropin DI is more susceptible to autodigestion than calotropin DII. During autodigestion no interconversion of one calotropin to another has occurred, as verified by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. Immunologically, both calotropins are closely related, but they differ from papain and ficin. Both calotropins have blocked N-terminal amino acid residues. Their C-terminal amino acid sequences, determined by treatment with carboxypeptidase Y, are -(Pro, Ala)-Ala-Val-Tyr for calotropin DI and -(Ala, Val)-Ala-Pro-Tyr for calotropin DII. The tryptic peptide maps of their reduced and S-carboxymethylated derivatives suggest that both calotropins share a high proportion of common regions in their amino acid sequences. Calotropins DI and DII are two distinct proteinases, and they do not appear to be produced by autodigestion of a single precursor. Although they are inert to the common synthetic substrates of papain and ficin, their specificities toward oxidized insulin B chain are comparable to those of papain and ficin.

UI	MeSH Term	Description	Entries
D007122	Immunoelectrophoresis	A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
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
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010450	Endopeptidases	A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.	Endopeptidase,Peptide Peptidohydrolases
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
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.
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D005779	Immunodiffusion	Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.	Gel Diffusion Tests,Diffusion Test, Gel,Diffusion Tests, Gel,Gel Diffusion Test,Immunodiffusions,Test, Gel Diffusion,Tests, Gel Diffusion