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Esterification of polyunsaturated fatty acids by various forms of immobilized lipase from Rhizomucor miehei
Author(s) -
Kosugi Yoshitsugu,
Kumar Roy Prodyut,
Chang Qinglong,
Shugui Cao,
Fukatsu Makoto,
Kanazawa Kenji,
Nakanishi Hiroshi
Publication year - 2000
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-000-545-7
Subject(s) - rhizomucor miehei , lipase , chemistry , polyunsaturated fatty acid , docosahexaenoic acid , substrate (aquarium) , chromatography , triacylglycerol lipase , carbodiimide , glutaraldehyde , organic chemistry , fatty acid , enzyme , oceanography , geology
Ethyl esterification specificity of a lipase from Rhizomucor miehei for polyunsaturated fatty acids (PUFA) was compared at 1 and 100 mM to study molecular recognition of PUFA. The chemical shift of methylene adjacent to carboxyl groups in the nuclear magnetic resonance spectrum of docosahexaenoic acid (DHA) in ethanol moved to a lower magnetic field as the concentration of DHA increased, suggesting that the degree of dissociation of DHA decreased. Specificity constants or apparent second‐order rate constants ( V max / K m or catalytic power) for 1 mM esterification by immobilized lipases were higher than the native lipase. Immobilized hydrophobic carrier of low mass transfer resistance for the esterification substrate may improve maximal velocity and affinity for the substrate. Higher specificity constants for 1 mM substrates were observed using immobilized lipases fixed on an anion exchange resin with glutaraldehyde and on a cation exchange carrier with carbodiimide. Activity yields measured with 1 mM PUFA substrate were high. For the substrates at a concentration of 100 mM, higher specific constants with these bifunctional reagents were not observed but higher activity yields were found.