Substrate Specificity of Lipases in Protease Preparations

Commercial protease preparations have been screened for their biocatalytic activity in the esterification of various fatty acids with 1-butanol. Of all protease preparations tested, only those from pineapple (bromelain) and Rhizopus sp. were found to contain active lipases. Similar to lipases from microorganisms, animals, and plants, such as papaya (Carica papaya) latex, lipases in the protease preparations of bromelain and Rhizopus sp. strongly discriminated against fatty acids having a cis-4 unsaturation, for example, all-cis-4,7,10,13,16,19-docosahexaenoic acid, cis-6 unsaturation, for example, petroselinic (cis-6-octadecenoic), γ-linolenic (all-cis-6,9,12-octadecatrienoic), and stearidonic (all-cis-6,9,12,15-octadecatetraenoic) acid, as well as cis-8 unsaturation, for example, dihomo-γ-linolenic (all-cis-8,11,14-eicosatrienoic) acid. Fatty acids having a cis-9 unsaturation, for example, oleic (cis-9-octadecenoic) and α-linolenic (all-cis-9,12,15-octadecatrienoic) acids, were very well accepted as substrates by both protease preparations. Fatty acids having hydroxy groups, for example, ricinoleic (12-hydroxy-cis-9-octadecenoic) and 12-hydroxystearic acid, epoxy groups, for example, trans-9,10-epoxystearic acid, and cyclopentenyl groups, for example, hydnocarpic [(11-(2‘-cyclopentenyl)undecanoic] and chaulmoogric [13-(2‘-cyclopentenyl)tridecanoic] acid, were also well accepted as substrates by both enzyme preparations. Keywords: Protease; lipase, biocatalyst; enzymatic esterification; fatty acid specificity