清酒醸造工程中の核酸系成分および関連酵素系について : (第2報)清酒麹の核酸分解酵素の性質について

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In the previous report we reported the distributions and changes of nucleic acid related substances and their degrading enzymes in the process of Koji making. In this report we will mention about the characteristics of the nucleic acid degrading enzymes.The homogenate of Koji was extracted with water a 5℃ for one hour. For this extraction water was the most suitable solvent. Of this crude enzyme solution, the follwing properties were revealed.1. The optimal pH was in the range of 4.0〜5.0 for RNase, 3.0〜4.0 for PDase and 4.0〜5.0 for PMase.2. The optimal temperature of RNase was in the range of 50〜60℃, and those of PDase and PMase were in the range of 45〜50℃.3. Heat stability for the RNase activity was reduced to about 50% by heating at 100℃ for 10 min, the PDase activity remained at a level of 40% at 60℃ for 10 min, and PMase was inactivated by heating at 60℃ for 10 min.4. Inhibition by metal ions was disclosed; Cu<++> and Zn^<++> inhibited the activity of RNase, and NaF and Na_2HPO_4 inhibited the PDase and PMase activities.5. In the digestion of yeast RNA by an crude enzyme solution of Koji, it was found that 3'-GMP was the main product among other derivatives. ATP was decomposed into 5'-AMP and 5'-IMP by the enzyme solution, and then 5'-AMP was redecomposed into 5'-IMP and hypoxanthine.
公益社団法人日本生物工学会の論文
1968-01-25