geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Quasi lip oxygenase activity of hemo globin a model for lip oxygenases ec 1.13.11.12


, : Quasi lip oxygenase activity of hemo globin a model for lip oxygenases ec 1.13.11.12. European Journal of Biochemistry 120(1): 161-168

Hb catalyses at low concentrations (0.01-1 .mu.M) a quasi-lipoxygenase reaction with remarkably high substrate specificity. Formation of lipohydroperoxides was demonstrated only with free 9-cis,12-cis-octadecadienoic acid (linoleic acid), its glycerol monoester, or 9-cis,12-cis-octadecadienol (linoleoyl alcohol). All-cis-9,12,15-octadecatrienoic acid (.alpha.-linolenic acid), all-cis-5,8,11,14-eicosatetraenoic acid (arachidonic acid) and all-cis-9,12,15-eicosatrienoic acid (dihomo-.gamma.-linolenic acid), phospholipids and biological membranes were not attacked. Saturated and unsaturated free fatty acids other than linoleic acid were strong inhibitors of the Hb-catalyzed oxygenation of linoleate. The reaction was also inhibited by cyanide, carbon monoxide, phenolic antioxidants and the lipoxygenase inhibitor salicylhydroxamic acid, as well as by some antiiinflammatory drugs (prednisolone, dexamethasone, acetylsalicylic acid); indomethacin did not inhibit. Protein inhibitors of lipoxygenase reactions were found in lung homogenates of various species [beef, sheep, pig, rabbit]. The molecular activity of the Hb-catalyzed oxygenation of linoleate was comparable with those of true lipoxygenases [rabbit reticulocyte, rat liver mitochondria, beef heart electron transfer particles] and was 8-fold higher than that of free hemin. Accordingly, the quasi-lipoxygenase activity of Hb was strongly suppressed by denaturation (heating, urea, pronase treatment, acid splitting). The apparent S0.5, the activation energy and the pH-optimum did not differ from those of most of the true lipoxygenases. The reaction product hydroperoxylinoleic acid but not hydrogen peroxide was an activator of the Hb-catalyzed oxygenation of linoleate. Hydroxylinoleic acid was a competitive inhibitor of the activation. At Hb concentrations higher than 1 .mu.M the quasi-lipoxygenase activity was completely suppressed presumably owing to the formation of inhibitory concentrations of hydroxylinoleate via the lipohydroperoxidase activity of Hb. The quasi-lipoxygenase reaction of Hb exhibits a suicidal behavior, caused by destruction of heme groups. The properties of the free hemin-catalyzed reaction were similar to those of Hb. Among other hemoproteins tested myoglobin and cytochrome P-450LM show comparable activities. The mechanism of the Hb-catalyzed oxygenation of linoleate seems to involve a change of valency of the heme iron.

US$29.90


Other references

Santanam, L.; Brame, R.S.; Lindsey, A.; Dewees, T.; Danieley, J.; Labrash, J.; Parikh, P.; Bradley, J.; Zoberi, I.; Michalski, J.; Mutic, S., 2013: Eliminating inconsistencies in simulation and treatment planning orders in radiation therapy. To identify deficiencies with simulation and treatment planning orders and to develop corrective measures to improve safety and quality. At Washington University, the DMAIIC formalism is used for process management, whereby the process is understo...

Merétey, K.; Elekes, E.; Bertók, L., 1970: Early 2-mercaptoethanol-resistant antibody production in endotoxin-treated rats. Experiments are reported concerning both natural and specific antibody production in endotoxin-treated rats.

Basalingappa, S., 1970: Environmental hazards to reproductives of Odontotermes assmuthi Holmgren. Indian Zool: 45-50

Bethke, R.M.; Pensack, J.M.; Kennard, D.C., 1947: The influence of hen's diet on growth of progeny. The rate of growth of chicks fed a yellow corn-soybean oil meal diet was influenced by the diet of their dams. Growth on a yellow corn-soybean oil meal diet was significantly greater in chicks from hens on a soybean oil meal-fish products diet tha...

Matsunaga T.; Kamiya S., 1987: Use of magnetic particles isolated from magnetotactic bacteria for enzyme immobilization. We report the novel use of magnetic particles isolated from magnetotactic bacteria. Magnetotactic bacteria were collected from enriched sludge by use of a magnetic harvesting apparatus. Magnetic particles separated from magnetotactic bacteria were...

Koerber, K.; Sass, G.; Kiemer, A.K.; Vollmar, A.M.; Tiegs, G., 2002: In vivo regulation of inducible no synthase in immune-mediated liver injury in mice. Inducible nitric oxide synthase (iNOS) has been shown to play an important role in the development of liver injury. iNOS deficiency protects mice from hemorrhage/resuscitation as well as from cytokine-mediated liver injury, for example, after admi...

Heerdt, P.M.; Gandhi, C.D.; Dickstein, M.L., 1998: Disparity of isoflurane effects on left and right ventricular afterload and hydraulic power generation in swine. The interaction between myocardial and vascular effects of anesthetics has a potential impact on how these drugs influence performance of the heart. Most studies have focused on volatile anesthetic effects on the left ventricle (LV) and systemic c...

Samsonov, P.F., 1962: On the article of I. I. Ashmarin and I. K. Musabaev, "Agglutination of a Strain of Water-Borne Leptospira with Human Serum". Meditsinskii Zhurnal Uzbekistana 5: 66-67

Osborne, C.Kent.; Schiff, R., 2005: Estrogen-receptor biology: continuing progress and therapeutic implications. Journal of Clinical Oncology 23(8): 1616-1622

Pardo, F.S.; Bristow, R.G.; Taghian, A.; Ong, A.; Borek, C., 1991: Role of transfection and clonal selection in mediating radioresistance. Transfected oncogenes have been reported to increase the radioresistance of rodent cells. Whether transfected nononcogenic DNA sequences and subsequent clonal selection can result in radioresistant cell populations is unknown. The present set of e...