Biomaterial Database

[Animal lipoxygenases. The nature of substrates and changes in conformation of reticulocyte lipoxygenase in its interaction with membranes]. 1985

V Z Lankin, and N T Gordeeva, and A K Tikhaze, and A M Vikhert

In the presence of natural (liver mitochondria and microsomes) and artificial (liposomes from saturated phosphatidyl cholines) membranes, the rate of oxidation of an emulgated polyunsaturated fatty acid by reticulocyte lipoxygenase sharply increases and correlates with the amount of polyunsaturated fatty acid incorporated into the membrane. Hydrolysis of egg lecithine polyunsaturated acyls by phospholipase A2 drastically increases the rate of their enzymatic oxidation. It was shown that 15-hydroperoxyarachidonate is incorporated into lecithine liposomes at a much slower rate that the non-oxidized arachidonic acid. Solubilization of membranes with a detergent leads to the disappearance of the activating effect. Addition of saturated lecithine liposomes results in quenching of protein fluorescence of reticulocyte lipoxygenase, thus suggesting conformational changes in the enzyme structure upon its interaction with the membrane. The experimental results suggest that free polyunsaturated membraneous fatty acids are physiological substrates for animal lipoxygenases. One possible reason for the elevated rate of the lipoxygenase reaction in membranes is the alteration of enzyme conformation upon its interaction with the membrane matrix.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008081	Liposomes	Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.	Niosomes,Transferosomes,Ultradeformable Liposomes,Liposomes, Ultra-deformable,Liposome,Liposome, Ultra-deformable,Liposome, Ultradeformable,Liposomes, Ultra deformable,Liposomes, Ultradeformable,Niosome,Transferosome,Ultra-deformable Liposome,Ultra-deformable Liposomes,Ultradeformable Liposome
D008084	Lipoxygenase	An enzyme of the oxidoreductase class primarily found in PLANTS. It catalyzes reactions between linoleate and other fatty acids and oxygen to form hydroperoxy-fatty acid derivatives.	Lipoxidase,Linoleate-Oxygen Oxidoreductase,Lipoxygenase-1,Lipoxygenase-2,Linoleate Oxygen Oxidoreductase,Lipoxygenase 1,Lipoxygenase 2,Oxidoreductase, Linoleate-Oxygen
D008297	Male		Males
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
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D008930	Mitochondria, Liver	Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)	Liver Mitochondria,Liver Mitochondrion,Mitochondrion, Liver
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010741	Phospholipases A	Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.