Inactivation of DNA polymerase 1, α-amylase and protease by basic dyes and inhibition of microbial growth

Abstract

Various organic substances as well as the dyes and the chromium compounds are contained in the waste dye liquor. As one of the methods of removing such organic materials, the activated sludge method has been frequently used. The microbial growth may be inhibited by the dyes and the chromium compounds in the process, and the inhibition induces a lowering of purification ability. The influences of these compounds on the microbial growth and DNA synthesis were reported as follows in the preceding paper~ I) The basic dyes inhibited strongly the microbial growth and DNA synthesis (0gawa et al. 1988). One of the causes of the inhibitions might be Stabilization of the double helix of DNA by intercalating the dye (0gawa et al. 1989a). 2) The inhibitions of the microbial growth and DNA synthesis by K2Cr207 were strong, despite no contribution to stabilization of the DNA helix. On the other hand, those by CrCI3 were weak, despite a positive contribution to stabilization of the DNA helix. Thus, for the purpose of proving other inhibitive factors than stabilization of the DNA helix, the inactivation of DNA polymerase i, a-amylase and protease by the basic dyes, and the inactivation of DNA polymerase 1 by the chromium compounds were examined, respectively. The following informations were obtained as the results. i) The inactivation of DNA polymerase 1 by Crystal Violet, a basic dye, was slightly weaker than that by K2Cr207, and that by CrCI~ was much weaker. 2) Activities of a-amylase and protease were competitively inhibited by the basic dyes. 3) The inhibition of DNA synthesis by Crystal Violet was due to the inactivation of DNA polymerase 1 and stabilization of the DNA helix. On the other hand, it by K2Cr207 was due to the inactivation of DNA polymerase i, and not to stabilization.