Heterocyclic amines (HCAs, Fig. 1) are mutagenic factors that are predominantly ingested as pyrolysis products of meats and fishes.1) To adsorb the HCAs on ligands, a cellulose coupled with a Cu-phthalocyanine derivative (Cu-PC, a related compound metal-porphyrin), so-called "blue cotton," was developed, 2,3) which was reported to be beneficial for callbacks and determinations of HCAs in environmental waters 2) and air-born particules.4) The adsorption of HCAs on the blue cotton is caused by hydrophobic p-p interaction between HCAs and Cu-PC coupled with cotton fiber. Peroxidase (POD), of which active cite is Fe-protoporphyrin, was reported to catalyze oxidative reactions of a wide range of mutagens and carcinogens including HCAs, thereby decreasing the mutagenicity and carcinogenicity. 5,6) In the above cases, metal-porphyrin derivatives serve as an adsorbent of HCAs or a catalysis of oxidative reaction of mutagens.On the other hand, we previously reported that some anion-exchangers modified with metal-tetrakis(sulfophenyl)-porphines (M-TSPP r ) exhibited a peroxidase (POD)-like activity and was applicable to the determination of hydrogen peroxide as a solid-mimesis of horse radish POD. 7,8) In the present paper, we investigated the POD-like activity of M-TSPP r s in the oxidation of HCAs to elucidate the usefulness of M-TSPP r s as a POD-like catalyst in the oxidation of HCAs. We revealed that some M-TSPP r s exhibit a similar POD-like activity for HCAs to horse radish POD. In particular, Fe-and Mn-TSPP r s catalyze the oxidation of 2-amino-3-methyl-imidazo[4,5-f ]quinoline (IQ) with hydrogen peroxide. The resulting IQ-dimmer has no mutagenicity in umutest. We elucidated that M-TSPP r can decrease mutagenicity of HCAs in vitro through its POD-like catalytic activity. ExperimentalMaterials Tetrakis(sulfophenyl)porphine (H 2 -TSPP) was purchased from Wako Junyaku Co. Ltd. (Osaka, Japan). Mutagenic HCAs (see Fig. 1), IQ, MeIQ, MeIQx, TrpP-1 and TrpP-2, were purchased from Wako Junyaku Co. Ltd. GluP-1 and GluP-2 (Chemsyn Science Laboratories, Lenaxa, Kansas, U.S.A.) were kindly donated from Prof. Hikoya Hayatsu (Shujitsu University). They were used without further purification. An anion-exchange resin, Amberlite IRA 900 (24-42 mesh) in nitrate form, was a manufacture of Organo Chemical Co. Ltd. (Tokyo, Japan). Other reagents were of analytical or reagent grade. umu-Test kit was purchased from Japan Immunoresearch Laboratories Co. Ltd. (Takasaki, Japan).Apparatus Absorption (UV/V) spectra and absorbances (abbr. "A") were measured on a Shimadzu UV-180 or a JASCO V-570 spectrophotometer with 10 mm quartz cells. HPLC system was constructed with a Shimadzu pump (LC-6A), a Shimadzu photodiode array detector (SPD-M6A) and a To elucidate the peroxidase (POD)-like catalytic activity of anion-exchange resins modified with metaltetrakis(sulfophenyl)porphine (M-TSPP r s), an oxidative reaction of seven mutagenic heterocyclic amines (HCAs) with hydrogen peroxide, which reaction is catalyzed by horse radish POD, was investigate...

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