Trypsin及びPepsinのPeriodateによる酸化

抄録

1) As trypsin was oxidized by sodium meta-periodate, the enzymatic activity diminished during the process of the reaction. After oxidizing for 2 hrs. at 5°, the oxidized trypsin which kept 91% of the original activity was obtained in crystalline form.
2) The optimum pH for proteolytic activities of trypsin and pepsin shifted toward neutral after periodate oxidation.
3) The optimum pH for proteolytic activities of trypsin and pepsin shifted toward neutral after periodate oxidation.
3) Trypsin which was after oxidized for 45 hours consumed 42 moles of periodate per mole of enzyme and the activity diminished to 40% using hemoglobin and casein as substrates. As compared with pepsin, trypsin consumed slowly but more oxidants per mole of enzyme, but the decrease in tryptic activity was far less.
4) In case of gelatin liquefaction it was found that diminution of tryptic and peptic activity was markedly different from the above-mentioned facts, i. e. pepsin retained 51% of gelatin liquefying activity after oxidation for 45 hrs, whereas trypsin retained only 5% after same period.
Considering together the above-mentioned fact and the tendency of consuming NaIO₄, it is deduced that trypsin possesses more groups which are slowly oxidized than pepsin and that these groups may contribute to the gelation liquefaction.