Biomaterial Database

Methionine modification impairs the C5-cleavage function of cobra venom factor-dependent C3/C5 convertase. 1998

Q Fu, and P McPhie, and D C Gowda

Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.

The complement-mediated lysis of guinea pig erythrocytes by cobra venom factor (CVF) decreased by 50-60% within 2 min of treatment with 5 mM sodium periodate at 0 degree C. This loss of activity paralleled modification of 3-4 Met; other amino acids and sugar residues of the oligosaccharide chains were not affected. Treatment with N-chlorosuccinimide or chloramine-T under conditions that specifically modified 3-4 readily-oxidizable Met also caused 50-60% loss of CVF activity. The secondary structure of CVF was not altered by these modifications. Methionine-modified CVF (MetCVF) supported the cleavage of factor B by factor D with equal efficiency as that of untreated CVF to form C3/C5 convertase (MetCVF,Bb) of the alternative pathway. MetCVF,Bb and CVF,Bb were indistinguishable with respect to C3 cleavage. However, the C5-cleavage ability of MetCVF,Bb was significantly lower than that of CVF,Bb. These results suggest the involvement of Met in CVF binding of C5.

UI	MeSH Term	Description	Entries
D008715	Methionine	A sulfur-containing essential L-amino acid that is important in many body functions.	L-Methionine,Liquimeth,Methionine, L-Isomer,Pedameth,L-Isomer Methionine,Methionine, L Isomer
D010504	Periodic Acid	A strong oxidizing agent.	Paraperiodic Acid,Periodic Acid (HIO4),Periodic Acids,Acid, Paraperiodic,Acid, Periodic,Acids, Periodic
D011415	Complement Factor B	A glycine-rich, heat-labile serum glycoprotein that contains a component of the C3 CONVERTASE ALTERNATE PATHWAY (C3bBb). Bb, a serine protease, is generated when factor B is cleaved by COMPLEMENT FACTOR D into Ba and Bb.	C3 Proactivator,C3PA,Complement 3 Proactivator,Factor B,Properdin Factor B,Bb Fragment of Factor B,Complement Factor B Fragment, Bb,Complement Factor B, Alternative Pathway,Complement Factor B-Derived Fragment Bb,Complement Factor Ba,Complement Factor Bb,Complement Protein B,Complement Protein Factor B,Properdin Factor Ba,Properdin Factor Bb,Properdin Factor Bf,Properdin Factor Bf F1,Bb, Complement Factor,Complement Factor B Derived Fragment Bb,Factor B, Complement,Factor B, Properdin,Factor Ba, Complement,Factor Ba, Properdin,Factor Bb, Complement,Factor Bb, Properdin,Factor Bf, Properdin,Proactivator, C3,Proactivator, Complement 3,Protein B, Complement
D003176	Complement C3	A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.	C3 Complement,C3 Precursor,Complement 3,Complement C3 Precursor,Complement Component 3,Precursor-Complement 3,Pro-C3,Pro-Complement 3,C3 Precursor, Complement,C3, Complement,Complement, C3,Component 3, Complement,Precursor Complement 3,Precursor, C3,Precursor, Complement C3,Pro C3,Pro Complement 3
D003182	Complement C5	C5 plays a central role in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C5 is cleaved by C5 CONVERTASE into COMPLEMENT C5A and COMPLEMENT C5B. The smaller fragment C5a is an ANAPHYLATOXIN and mediator of inflammatory process. The major fragment C5b binds to the membrane initiating the spontaneous assembly of the late complement components, C5-C9, into the MEMBRANE ATTACK COMPLEX.	C5 Complement,Complement 5,Complement C5, Precursor,Complement Component 5,Precursor C5,Pro-C5,Pro-complement 5,C5, Complement,C5, Precursor,C5, Precursor Complement,Complement, C5,Component 5, Complement,Precursor Complement C5,Pro C5,Pro complement 5
D004546	Elapid Venoms	Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.	Cobra Venoms,Elapidae Venom,Elapidae Venoms,Naja Venoms,Cobra Venom,Elapid Venom,Hydrophid Venom,Hydrophid Venoms,King Cobra Venom,Naja Venom,Ophiophagus hannah Venom,Sea Snake Venom,Sea Snake Venoms,Venom, Cobra,Venom, Elapid,Venom, Elapidae,Venom, Hydrophid,Venom, King Cobra,Venom, Naja,Venom, Ophiophagus hannah,Venom, Sea Snake,Venoms, Cobra,Venoms, Elapid,Venoms, Elapidae,Venoms, Hydrophid,Venoms, Naja,Venoms, Sea Snake
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
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
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
D013388	Succinimides	A subclass of IMIDES with the general structure of pyrrolidinedione. They are prepared by the distillation of ammonium succinate. They are sweet-tasting compounds that are used as chemical intermediates and plant growth stimulants.	Butanimides,Pyrrolidinediones