Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of homocysteine on the synthesis of arterial prostacyclin (PGI2) were investigated. Homocysteine at 10 mM and 1 mM concentration inhibited PGI2 synthesis from both exogenous and endogenous arachidonic acid. While concentrations of 100 microM and 1 microM stimulated PGI2 synthesis. Similar inhibitory effects of H2O2 on PGI2 synthesis were observed. High concentrations (100 microM and 500 microM) of H2O2 inhibited PGI2 production while low concentrations (1 microM) of H2O2 stimulated it. Catalase overcame the inhibitory effect of H2O2 (100 microM). Homocysteine induced O2 uptake and catalase inhibited the O2 uptake by homocysteine. Thus the inhibitory and stimulatory effect of homocysteine may be dependent on the oxidation of homocysteine and subsequent H2O2 generation.
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PMID:Peroxide mediated effects of homocysteine on arterial prostacyclin synthesis. 352 44

Homocysteine is considered to be an important risk factor for cancer as well as cardiovascular diseases. To clarify whether homocysteine has potential carcinogenicity, we investigated formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), which is known to be correlated with the incidence of cancer, induced by homocysteine in human cultured cell lines. Homocysteine increased the amount of 8-oxodG in human leukemia cell line HL-60, whereas the amount of 8-oxodG in its hydrogen peroxide (H(2)O(2))-resistant clone HP100 was not increased. We investigated the mechanism for oxidative DNA damage by homocysteine using (32)P-labeled DNA fragments obtained from human tumor suppressor genes and a proto-oncogene. There were two mechanisms by which homocysteine caused DNA damage in the presence of Cu(II). A low concentration of homocysteine (20 microM) frequently induced piperidine-labile sites at thymine residues, whereas a high concentration of homocysteine (100 microM) resulted in damage principally to guanine residues. Catalase inhibited DNA damage by 20 microM homocysteine, indicating the participation of H(2)O(2), but was ineffective in preventing DNA damage by 100 microM homocysteine. Experiments using a singlet oxygen probe showed that 100 microM homocysteine enhanced chemiluminescence intensity in deuterium oxide more than that in H(2)O. These results indicated that the metal-dependent DNA damage through H(2)O(2) is likely to be a more relevant mechanism for homocysteine carcinogenicity.
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PMID:Oxidative damage to cellular and isolated DNA by homocysteine: implications for carcinogenesis. 1278 61