Isolation and Characterization of the Oil Bodies and Oleosin of Coconut (Cocos nucifera L.)

Abigail Joy  Rodelas; Ellen  Regalado; Dennis  Bela-ong; Roberta  Garcia; Antonio  Laurena; Evelyn Mae Tecson  Mendoza

Abigail Joy Rodelas
Ellen Regalado
Dennis Bela-ong Institute of Plant Breeding, Crop Science Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna, Philippines
Roberta Garcia Institute of Plant Breeding, Crop Science Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna, Philippines
Antonio Laurena Institute of Plant Breeding, Crop Science Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna, Philippines
Evelyn Mae Tecson Mendoza Institute of Plant Breeding, Crop Science Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna, Philippines

Keywords: oleosin, oil body, coconut, Cocos nucifera, oil body storage protein

Abstract

Oil bodies were isolated from the solid endosperm of 11–12 month old coconut and purified by sucrosedensity gradient washing, urea washing and floatation centrifugation. Under light microscope, purifiedoil bodies showed two types of small and large oil bodies: about 90% with diameter of 0.5–4.0 μm and10%, 10–40 μm, respectively. The oil bodies consisted of 97% triacylglycerols, phospholipids(phosphatidylethanoloamine and phosphatidylcholine) and the oil body storage protein oleosin. Puri-fied oleosin showed one band of 14400 on SDS-PAGE. Two-dimensional electrophoresis resolved oneband of 14400 with an isoelectric pH between 9 and 10. The 14400 band had an N-terminal amino acidsequence of GEERR or GEEER. Additional urea washings of the coconut oil bodies followed by etherdelipidation revealed two oleosin bands of 14400 and 11000 Mr on SDS-PAGE.