Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P36969 (phospholipid hydroperoxide glutathione peroxidase)
 344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat liver microsomal glutathione transferase was found to display glutathione peroxidase activity toward a variety of oxidized lipids. 1-Linoleoyl-2-palmitoyl phosphatidylcholine hydroperoxide, 2-linoleoyl-1-palmitoyl phosphatidylcholine hydroperoxide, 2-linoleoyl-1-palmitoyl phosphatidylethanolamine hydroperoxide, and cholesteryl linoleate hydroperoxide all served as substrates (0.02, 0.04, 0.02, and 0.02 mumol/min mg, respectively). The phospholipid hydroperoxide glutathione peroxidase activity of the enzyme was found not to require detergent and increased when liposomes containing peroxidized phospholipid were fused with liposomes containing microsomal glutathione transferase. Methyl linoleate ozonide serves as a very efficient substrate for the microsomal glutathione transferase. The unactivated and N-ethylmaleimide-activated enzyme displayed specific activities of 0.74 and 5.9 mumol/min mg, respectively. Upon examination of a series of 4-hydroxyalk-2-enals it was found that the catalytic efficiency of the enzyme increases from the 4-hydroxyhept-2-enal up to the 4-hydroxytetradec-2-enal. The specific activities with the various 4-hydroxyalk-2-enals tested varied between 0.28 and 0.95 mumol/min mg. The phospholipid dependence of the microsomal glutathione transferase was examined in proteoliposomes formed by cholate dialysis. Phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, and rat liver microsomal phospholipids could all be used successfully to reconstitute the enzyme. In conclusion, microsomal glutathione transferase can detoxify a number of lipid peroxidation products as well as a fatty acid ozonide. The results imply a protective role for the enzyme under conditions of oxidative stress.
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PMID:Microsomal glutathione transferase: lipid-derived substrates and lipid dependence. 762 26

Anuran toxins released from the skin glands are involved in defence against predators and microorganisms. Secretion from parotoid macroglands of bufonid toads is a rich source of bioactive compounds with the cytotoxic, cardiotoxic and hemolytic activity. Bufadienolides are considered the most toxic components of the toad poison, whereas the protein properties are largely unknown. In the present work, we analysed the cardio-, myo-, and neurotropic activity of extract and the selected proteins from Bufo bufo parotoids in in vitro physiological bioassays carried out on two standard model organisms: beetles and frogs. Our results demonstrate a strong cardioactivity of B. bufo gland extract. The toad poison stimulates (by 16%) the contractility of the insect heart and displays the cardioinhibitory effect on the frog heartbeat frequency (a 27% decrease), coupled with an irreversible cardiac arrest. The gland extract also exhibits significant myotropic properties (a 10% decrease in the muscle contraction force), whereas its neuroactivity remains low (a 4% decrease in the nerve conduction velocity). Among identified peptides present in the B. bufo parotoid extract are serine proteases, muscle creatine kinase, phospholipid hydroperoxide glutathione peroxidase, cytotoxic T-lymphocyte protein, etc. Some proteins contribute to the cardioinhibitory effect. Certain compounds display the paralytic (myo- and neurotropic) properties. As the toad gland extract exhibits a strong cardiotoxic activity, we conclude that the poison is a potent agent capable of slaying a predator. Our results also provide the guides for the use of toad poison-peptides in therapeutics and new drug development.
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PMID:Toxic activity and protein identification from the parotoid gland secretion of the common toad Bufo bufo. 2938 76