Biomaterial Database

Free metal ion-independent oxidative damage of collagen. Protection by ascorbic acid. 1994

C K Mukhopadhyay, and I B Chatterjee

Department of Biochemistry, University College of Science, Calcutta, India.

In this paper we demonstrate that in the absence of free metal ions, active oxygen species, generated by activated macrophages or xanthine/xanthine oxidase (XOD), carry out oxidative degradation of collagen fibrils type I in conjunction with proteases. The collagen degradation is completely prevented by ascorbate (AH2) but not by catalase. The free metal ion-independent collagen degradation is a two-step process: (i) oxidation of collagen and (ii) subsequent proteolytic cleavage of the oxidatively modified collagen. AH2 completely prevents collagen oxidation and thereby protects the collagen from subsequent proteolytic degradation. This is in contrast to free metal ion-catalyzed spontaneous fragmentation of collagen, which is accelerated by AH2 and inhibited by catalase (Kato, Y., Uchida, K., and Kawakishi, S. (1992) J. Biol. Chem. 267, 23646-23651). Studies using xanthine/XOD and model polypeptides, namely, poly-L-Pro, poly-L-hydroxyproline, poly-L-Lys, and poly(Pro-Gly-Pro) indicate that although O2-. is needed along with XOD, oxidation of model polypeptides appears to be a direct function of XOD iron, which is also stimulated by cytochrome P450.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008262	Macrophage Activation	The process of altering the morphology and functional activity of macrophages so that they become avidly phagocytic. It is initiated by lymphokines, such as the macrophage activation factor (MAF) and the macrophage migration-inhibitory factor (MMIF), immune complexes, C3b, and various peptides, polysaccharides, and immunologic adjuvants.	Activation, Macrophage,Activations, Macrophage,Macrophage Activations
D008297	Male		Males
D008670	Metals	Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)	Metal
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D002374	Catalase	An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.	Catalase A,Catalase T,Manganese Catalase,Mn Catalase
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D003094	Collagen	A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).	Avicon,Avitene,Collagen Felt,Collagen Fleece,Collagenfleece,Collastat,Dermodress,Microfibril Collagen Hemostat,Pangen,Zyderm,alpha-Collagen,Collagen Hemostat, Microfibril,alpha Collagen