Biomaterial Database

Lysine-49-phospholipases A2 from Trimeresurus flavoviridis venom are membrane-acting enzymes. 1995

Y Shimohigashi, and A Tani, and H Matsumoto, and K Nakashima, and Y Yamaguchi

Department of Chemistry, Kyushu University, Fukuoka.

Basic proteins I and II (BP-I and BP-II) isolated from the venom of Trimeresurus flavoviridis (Habu snake) are isozymes of highly active Asp-49 phospholipase A2 (Asp-49-PLA2) and classified into the group Lys-49-PLA2. BP-II was found to elicit a strong contraction of guinea pig ileum, and this activity was inhibited completely by 1 microM indomethacin, an inhibitor of the arachidonate cascade. BP-II was inactive in the Ca(2+)-free medium, and p-bromphenacylated His-48-BP-II was also inactive. BP-II exhibited no binding affinity for the cells expressing PLA2 receptors. These results indicated that the contraction elicited by BP-II is due to the hydrolytic action of BP-II, liberating arachidonic acid from the ileum phospholipid biomembranes. In spite of its limited lipolytic activities (av. 0.9% of Asp-49-PLA2) against monomers and micelles of synthetic phospholipids, BP-II hydrolyzed considerably strongly the phospholipids in the artificial bilayer vesicles. Arachidonic acid released from liposomes of beta-arachidonoyl-gamma-stearoyl-L-alpha-phosphatidylcholine was determined by HPLC, and the activity of BP-II was estimated to be about 75% as compared to Asp-49-PLA2. Liposomes encapsulating carboxyfluorescein exhibited a strong dye-leakage induced by BP-II in a concentration-dependent manner, only in the Ca(2+)-containing buffer. The net result from all these observations was that BP-II, a Lys-49-PLA2, is an enzyme that hydrolyzes the membrane phospholipids. In contrast to BP-II, BP-I was found to be considerably weak in hydrolyzing membrane phospholipids, although its activities were distinct. BP-I and BP-II share a common sequence with the sole exception of Asp-67 (BP-I) and Asn-67 (BP-II) in the aligned sequences. This implies that the amino acid at position 67 of Lys-49-PLA2s is the residue required for discriminatory recognition of beta-arachidonoyl-phospholipid membranes.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
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
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D010741	Phospholipases A	Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D003435	Crotalid Venoms	Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.	Bothrops Venom,Crotalidae Venoms,Pit Viper Venoms,Rattlesnake Venoms,Crotactin,Crotalid Venom,Crotalin,Crotaline Snake Venom,Crotalotoxin,Crotamin,Pit Viper Venom,Rattlesnake Venom,Snake Venom, Crotaline,Venom, Bothrops,Venom, Crotalid,Venom, Crotaline Snake,Venom, Pit Viper,Venom, Rattlesnake,Venoms, Crotalid,Venoms, Crotalidae,Venoms, Pit Viper,Venoms, Rattlesnake,Viper Venom, Pit
D005452	Fluoresceins	A family of spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one derivatives. These are used as dyes, as indicators for various metals, and as fluorescent labels in immunoassays.	Tetraiodofluorescein