Cellulase occurs in multiple active forms in ripe avocado fruit mesocarp.

Area of Science:

• Biochemistry
• Plant Science
• Enzymology

Background:

• Avocado fruit (Persea americana Mill. cv Hass) contains various enzymes crucial for ripening.
• Cellulase activity is a key factor in fruit softening and texture changes.

Purpose of the Study:

• To investigate the diversity of cellulase forms in ripe Hass avocado fruit.
• To characterize the properties of these cellulase isoforms.

Main Methods:

• Extraction of crude protein from ripe avocado fruit.
• Separation of cellulase forms using native isoelectric focusing (pH 4-7).
• Visualization and characterization via activity staining (Congo red) and immunostaining.

Main Results:

• At least 11 distinct cellulase forms were identified in avocado extracts.
• All identified forms were acidic proteins with isoelectric points ranging from pH 5.10 to 6.80.
• Predominant cellulase forms exhibited isoelectric points at pH 5.60, 5.80, 5.95, and 6.20.
• All 11 forms were immunologically related and shared a molecular mass of 54 kilodaltons.

Conclusions:

• Ripe Hass avocado fruit possesses a complex mixture of cellulase isoforms.
• These cellulase forms are immunologically similar, suggesting a common origin or structural relationship.
• Understanding these multiple cellulase forms can provide insights into avocado fruit ripening and softening processes.