Influence of fullerene (C60) derivatives on M-MuLV reverse transcriptase activity is investi- gated. Two water-soluble fullerene derivatives, fullerol (C60(OH)23-24) and trimalonic acid C60 (TMA C60, C63(COOH)6) are used in the experiments and their effects on in vitro reverse transcription-polymerase chain reaction (RT-PCR) of β-actin mRNA in HeLa cells are determined. PCR products are detected by agarose gel electrophoresis. It is found that the amounts of PCR products decrease with addition of either of two fullerene derivatives to RT reaction mixture. The inhibition of fullerene derivatives is dose-dependent, and IC50 values of fullerol and TMA C60 are 0.089 and 0.039 mmol/L, respectively. The amount of PCR products obtained by direct addition of fullerol or TMA C60 to PCR are greater than those obtained by addition of the equivalent amount of fullerol or TMA C60 to RT, indicating an inhibitory ef- fect of fullerol or TMA C60 on RT. The compensative experiment of M-MuLV reverse transcriptase shows that increasing enzyme amounts can antagonize the activity of fullerol or TMA C60. These results imply that fullerenes can inhibit M-MuLV reverse transcriptase activity, with the inhibition of TMA C60 slightly stronger than fullerol, and that their potential in treatment of diseases induced by RNA viruses such as leukemia virus needs further investigation.
MENG Xianmei CHEN Zhe LI Bo ZHANG Yufei ZHAO Dongxu YANG Xinlin
Activities of trimalonic acid fullerene (TMA C_60) on DNA restrictive enzymatic reaction were investigated by using two restrictive endonucleases Hind III and EcoR I and plasmid pEGFP-N1 with single restric-tive site for both enzymes. Meanwhile, TMA C60 was also tested to clarify its effects on polymerase chain reaction (PCR) with the catalyst of Taq DNA polymerase and the template of plasmid pEGFP-N1. The products from restrictive reactions or PCR were detected by agarose gel electrophoresis. It was found that the product amounts from restrictive reactions or PCR decreased significantly with addition of TMA C60. The inhibition by TMA C60 was dose-dependent and IC50 values for reactions of Hind III, EcoR I and PCR were 16.3, 6.0 and 6.0 μmol/L, respectively. Addition of two scavengers of reactive oxygen species (ROS), L-ascorbic acid-2-phosphate ester magnesium and sodium azide at the con-centrations of 2―10 mmol/L did not antagonize the activities of TMA C60 against PCR and two restrictive reactions. However, increase of Taq DNA polymerase amounts in PCR system antagonized the activities of TMA C60. These data implied that TMA C60 was able to inhibit the activities of the three above-mentioned enzymes involved in DNA metabolism, and that this inhibition probably did not correlate to ROS.
