Submitted to: Oklahoma Academy of Science Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 11/14/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Exochitinase (chitobiase) is an enzyme that has been associated with the defense against fungal invasion in plant tissue. The plant produces these enzymes and they are released and synthesis enhanced in the presence of a fungal pathogen. Latent fungal pathogens invade the fruit during net development and remain dormant until fruit maturity (40 days after flowering). The induction of latency and the stimulation to continue infection at fruit maturity is poorly understood. One hypothesis is that fruit defense enzymes are present early in fruit development but, decrease in activity as the fruit matures, therefore, rendering the fruit more susceptible to fungal pathogens. Chitobiase activity was observed in mesocarp and exocarp cantaloupe tissue, with the highest activity in fruit mesocarp. Acetone precipitated proteins were applied to an anion and cation exchange column. Two peaks were observed. The anionic peak had the emost activity and this fraction was applied to a size-exclusion column wit showed on peak of chitobiase activity. SDS-PAGE of the chitobiase fraction indicated one protein band at 44 kD. Further chromatography of exocarp tissue showed that 10-day fruit had the highest chitobiase activity when compared to older fruit samples.