Biomaterial Database

Substrates for the assay of alpha-L-iduronidase. 1978

J N Thompson

Procedures are described for the preparation of two disaccharides, 4-O-alpha-L-iduronosyl-2,5-anhydro[3H]mannitol and 3-O-alpha-L-iduronosyl-2,5-anhydro[3H]-talitol, from heparin and dermatan sulfate, respectively. These disaccharides lend themselves to an easy assay of alpha-L-iduronidase which is based on the fractionation of the liberated neutral anhydro[3H]mannitol or anhydro[3H]talitol from the unreacted substrate by adsorption of the latter to Dowex 1. Investigation of the reaction conditions showed that the alpha-L-iduronidase activity (enzyme from human fibroblasts and Helix pomatia) was optimal at pH 3.6 in acetate buffer containing 0.01 M NaCl with iduronosyl-2,5-anhydro[3H]mannitol as substrate. For iduronosyl-2,5-anhydro[3H]talitol the pH optimum was 4.0 with the H. pomatia enzyme. The KM for iduronosyl-2,5-anhydro[3H]mannitol was 0.23 mM with human fibroblasts and 0.04 mM with Helix enzyme; a KM value of 0.02 mM was determined for iduronosyl-2,5-anhydro[3H]talitol with the Helix alpha-L-iduronidase.

UI	MeSH Term	Description	Entries
D007067	Iduronic Acid	Component of dermatan sulfate. Differs in configuration from glucuronic acid only at the C-5 position.	Iduronate,Acid, Iduronic
D007068	Iduronidase	An enzyme that hydrolyzes iduronosidic linkages in desulfated dermatan. Deficiency of this enzyme produces Hurler's syndrome. EC 3.2.1.76.	alpha-L-Idosiduronase,alpha-L-Iduronidase,alpha L Idosiduronase,alpha L Iduronidase
D008353	Mannitol	A diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity.	(L)-Mannitol,Osmitrol,Osmofundin
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D003871	Dermatan Sulfate	A naturally occurring glycosaminoglycan found mostly in the skin and in connective tissue. It differs from CHONDROITIN SULFATE A (see CHONDROITIN SULFATES) by containing IDURONIC ACID in place of glucuronic acid, its epimer, at carbon atom 5. (from Merck, 12th ed)	Chondroitin Sulfate B,beta-Heparin,Sulfate B, Chondroitin,Sulfate, Dermatan,beta Heparin
D004187	Disaccharides	Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.	Disaccharide
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D006026	Glycoside Hydrolases	Any member of the class of enzymes that catalyze the cleavage of the glycosidic linkage of glycosides and the addition of water to the resulting molecules.	Endoglycosidase,Exoglycosidase,Glycohydrolase,Glycosidase,Glycosidases,Glycoside Hydrolase,Endoglycosidases,Exoglycosidases,Glycohydrolases,Hydrolase, Glycoside,Hydrolases, Glycoside
D006372	Helix, Snails	A genus of chiefly Eurasian and African land snails including the principal edible snails as well as several pests of cultivated plants.	Helix (Snails),Snails Helix
D006493	Heparin	A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts.	Heparinic Acid,alpha-Heparin,Heparin Sodium,Liquaemin,Sodium Heparin,Unfractionated Heparin,Heparin, Sodium,Heparin, Unfractionated,alpha Heparin