Abstract
Experiments were conducted, (1) to explain the behaviors of the macerating enzymes which are present in the soft rotted kaki fruit invaded by Gloeosporium kaki, and (2) to ascertain whether these enzymes are produced by the pathogen or the host.
Two kinds of the macerating enzymes, characteristic of a protein or a protein-like substance, were separated by zone electrophoresis from the softened fruits. Both enzymes were capable of macerating the disk of kaki fruit more readily than that of potato tuber. The maximum activities of them were found at pH range of 4.0∼5.0 and 4.5∼5.0, respectively. These revealed little to no activities on pectic solutions and caused no change in the O2 uptake of the kaki disks at an early stage of the incubation. These properties resemble those of “macerating enzyme” from Clostridium felsineum var. sikokianum.
The same enzymes as in the diseased fruit were also isolated from the healthy fruit. The experiments with the juices as well as the crude enzyme preparations indicated that no difference in the macerating behavior was recognizable between the diseased and the healthy fruits. Besides, the macerating enzymes found in the soft rotted fruits apparently differed from those in the cultural filtrate of G. kaki. These findings confirm the evidence that the softening of the fruit invaded by G. kaki are caused by the macerating enzymes from the host.
