Conformational Similarity between the Active Sites of a Sunflower Seedlings Lipase and a Porcine Pancreatic Lipase

Sellema Bahri; Raja Marrakchi; Amel Benammar-ElGaaied; Jeannette Ben Hamida

Sellema Bahri Laboratoire de Biochimie, D�partement de Biologie, Facult� des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisia.
Raja Marrakchi Laboratoire de G�n�tique, Immunologie et Pathologies Humaines, D�partement de Biologie, Facult� des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisia.
Amel Benammar-ElGaaied Laboratoire de G�n�tique, Immunologie et Pathologies Humaines, D�partement de Biologie, Facult� des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisia.
Jeannette Ben Hamida Laboratoire de Biochimie, D�partement de Biologie, Facult� des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisia.

Keywords: Triacylglycerol lipase, oleosomes, polyclonal antibodies, cross-reactivity, Helianthus annuus L

Abstract

A true triacylglycerol lipase was detected in germinating sunflower (Helianthus annuus L.) seedlings associated to oleosomes. This enzyme that has not yet been identified was partially purified as shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) (10%): Two protein bands, of 61 and 66 kDa, were isolated from the active lipase fraction. Polyclonal antibodies (PAbs) directed against each protein band were produced. Only PAbs against the 61 kDa protein band (P-61) were able to inhibit the total lipolytic activity of our preparation. Hence, only the 61 kDa protein carries the sunflower lipase activity. The relationship between a pure porcine pancreatic lipase and the P-61 purified sunflower lipolytic fraction was investigated, leading to the first evidence of cross reaction between the porcine pancreatic lipase and the P-61 sunflower lipase fraction.These results are in agreement with common epitopes to the porcine pancreatic lipase and the sunflower P-61.