Biomaterial Database

Reconstitution of lymphocyte 5'-nucleotidase in lipid bilayers: behaviour and interaction with concanavalin A. 1985

F J Sharom, and I Lorimer, and M P Lamb

Pure 5'-nucleotidase (EC 3.1.3.5) and a membrane glycoprotein fraction (partially purified 5'-nucleotidase) were isolated from pig lymphocyte plasma membrane by affinity chromatography techniques, using the cationic detergent dodecyltrimethylammonium bromide as a solubilizing agent. A detergent-dialysis technique was used to reconstitute both partially purified and pure enzyme into large unilamellar phospholipid vesicles, where it remains functional. 5'-Nucleotidase is relatively unstable in detergent solutions, but is highly stable once reconstituted into lipid vesicles. Arrhenius plots of the enzyme in bilayers of dimyristoyl phosphatidylcholine show a break point at 22-23 degrees C, with a different activation energy above and below the phospholipid gel-to-liquid crystalline phase transition. 5'-Nucleotidase in intact plasma membrane is inhibited more than 95% by concanavalin A in a positively cooperative fashion (Hill coefficient = 2.1), as is partially purified reconstituted enzyme. Purification of the enzyme before reconstitution results in less than 50% inhibition by concanavalin A and a complete loss of positive cooperativity (Hill coefficient less than 1.0). The inhibition properties of the enzyme can be fully restored by co-reconstituting pure 5'-nucleotidase with the remaining lymphocyte glycoproteins.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008051	Lipid Bilayers	Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.	Bilayers, Lipid,Bilayer, Lipid,Lipid Bilayer
D008214	Lymphocytes	White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.	Lymphoid Cells,Cell, Lymphoid,Cells, Lymphoid,Lymphocyte,Lymphoid Cell
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009708	Nucleotidases	A class of enzymes that catalyze the conversion of a nucleotide and water to a nucleoside and orthophosphate. EC 3.1.3.-.
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003208	Concanavalin A	A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.
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
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
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog