Abstract
(1) Acid invertase was detected in cell walls of persimmon and soy bean callus. (2) The cell wall-bound invertases were solubilized by treatment with several chemicals. The degree of solubilization was drastically influenced by pH values and kind of buffer. About 70% of cell wall-bound invertase activity from both sources was solubilized with various kinds of 1 M salt solutions. However, about 15-20 % of invertase activity remained in the cell walls even after repeated solubilization with 1 M NaCI. Triton X-100 and sucrose did not release invertases from cell walls of both callus cells. (3) Invertase solubilized from persimmon callus cells was adsorbed on cell walls of persimmon and morning-glory callus cells. The enzyme released from morning-glory callus cells was adsorbed on cell walls of persimmon callus cells. (4) Properties of both cell wall-bound invertases were investigated. The optimum pH values of the persimmon and soy bean enzymes were 4.0 and 4.5, respectively. The soy bean enzyme was stable at pH values above 4. The persimmon enzyme was stable between pH 4 and 7.5. The optimum temperature for both enzymes was about 45°C. Both enzymes were stable at a temperature lower than 35°C, but above 35°C they rapidly lost their activity. Both enzymes hydrolyzed sucrose five times as fast as raffinose. Km values of the persimmon and soy bean enzymes for sucrose were 1.4 and 0.9 mM, respectively.
