title: A thermoactive uropygial esterase from chicken: purification, characterisation and synthesis of flavour esters.
abstract: A lipolytic activity was located in the chicken uropygial glands, from which a carboxylesterase (CUE) was purified. Pure CUE has an apparent molecular mass of 50 kDa. The purified esterase displayed its maximal activity (200 U/mg) on short-chain triacylglycerols (tributyrin) at a temperature of 50°C. No significant lipolytic activity was found when medium chain (trioctanoin) or long chain (olive oil) triacylglycerols were used as substrates. The enzyme retained 75% of its maximal activity when incubated during 2h at 50°C. The NH(2)-terminal amino acid sequence showed similarities with the esterase purified recently from turkey pharyngeal tissue. Esterase activity remains stable after its incubation during 30 min in presence of organic solvents such as hexane or butanol. CUE is a serine enzyme since it was inactivated by phenylmethanesulphonyl fluoride (PMSF), a serine-specific inhibitor. The purified enzyme, which tolerates the presence of some organic solvent and a high temperature, can be used in non-aqueous synthesis reactions. Hence, the uropygial esterase immobilised onto CaCO(3) was tested to produce the isoamyl and the butyl acetate (flavour esters). Reactions were performed at 50°C in presence of hexane. High synthesis yields of 91 and 67.8% were obtained for isoamyl and butyl acetate, respectively.
authors.affiliation: Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS route de Soukra, Sfax, Tunisia. ahmed_fendri@yahoo.fr
authors.forename: Ahmed
authors.initials: A
authors.lastname: Fendri
authors.forename: Hanen
authors.initials: H
authors.lastname: Louati
authors.forename: Mohamed
authors.initials: M
authors.lastname: Sellami
authors.forename: Héla
authors.initials: H
authors.lastname: Gargouri
authors.forename: Nabil
authors.initials: N
authors.lastname: Smichi
authors.forename: Zied
authors.initials: Z
authors.lastname: Zarai
authors.forename: Imen
authors.initials: I
authors.lastname: Aissa
authors.forename: Nabil
authors.initials: N
authors.lastname: Miled
authors.forename: Youssef
authors.initials: Y
authors.lastname: Gargouri
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D004950:Esterases / Q000737:chemistry* / Q000302:isolation & purification*; D004952:Esters / Q000138:chemical synthesis*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008066:Lipolysis; D008969:Molecular Sequence Data; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014105:Tosyl Compounds / Q000494:pharmacology; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: D004952:Esters; D012997:Solvents; D014105:Tosyl Compounds; D014753:Vinyl Compounds; C100195:vinyl ether; C003614:4-toluenesulfonyl fluoride; D004950:Esterases