SDS-PAGE AND TWO-DIMENSIONAL ELECTROPHORESIS DETERMINATION OF PROTEIN FROM PEEL AND PULP TISSUES OF RIPENING DURIAN FRUIT

Durian (Durio zibethinus Murr.) is a tropical fruit with thick wooden skin and sharp spines covering a creamy yellow edible aril part. Ripening of the fruit is characterized by a climacteric raise of respiration and ethylene production. These physiological changes are accompanied by aril softening and various changes in chemical compositions which lead to an overall eating quality. SDS-PAGE was used to separate soluble proteins extracted from peel and pulp tissue at different ripening stages. SDS-PAGE analysis revealed a relatively similar but different in relative abundance of some polypeptide species between peel and pulp tissues during ripening. Two-dimensional electrophoreses were performed on soluble proteins from ripe and unripe peel and pulp tissues. 2D-PAGE protein profile of ripening durian peel and pulp can be characterized into six groups of polypeptide species depending on their constitutively express, significantly increase or decrease, slightly increase or decrease in their relative abundance or disappearing as the fruit become ripe. Further analysis of these ripening specific polypeptide species by either N-terminal sequencing or mass spectrometry may help to reveal a rather complex ripening behavior of this fruit.