| Title : Probing a functional role of Glu87 and Trp89 in the lid of Humicola lanuginosa lipase through transesterification reactions in organic solvent - Holmquist_1995_J.Protein.Chem_14_217 |
| Author(s) : Holmquist M , Clausen IG , Patkar S , Svendsen A , Hult K |
| Ref : J Protein Chem , 14 :217 , 1995 |
| Abstract : To reveal the functional role of Glu87 and Trp89 in the lid of Humicola lanuginosa lipase, site-directed mutagenesis at Glu87 and Trp89 was carried out. The catalytic performance of wild-type and mutated lipases was studied in transesterification reactions in cyclohexane at a controlled water activity. Two different acyl donors were used in the investigation: tributyrin, a natural substrate for a lipase, and vinyl butyrate, an activated ester suitable for fast and efficient lipase-catalyzed transformations in preparative organic synthesis. As acyl acceptor 1-heptanol was used. The Glu87Ala mutation decreased the Vmax,app value with tributyrin and vinyl butyrate by a factor of 1.5 and 2, respectively. The Km,app for tributyrin was not affected by the Glu87Ala mutation, but the Km,app for vinyl butyrate increased twofold compared to the wild-type lipase. Changing Trp89 into a Phe residue afforded an enzyme with a 2.7- and 2-fold decreased Vmax,app with the substrates tributyrin and vinyl butyrate, respectively, compared to the wild-type lipase. No significant effects on the Km,app values for tributyrin or vinyl butyrate were seen as a result of the Trp89Phe mutation. However, the introduction of a Glu residue at position 89 in the lid increased the Km,app for tributyrin and vinyl butyrate by a factor of > 5 and 2, respectively. The Trp89Glu mutated lipase could not be saturated with tributyrin within the experimental conditions (0-680 mM) studied here. With vinyl butyrate as a substrate the Vmax,app was only 6% of that obtained with wild-type enzyme. |
| ESTHER : Holmquist_1995_J.Protein.Chem_14_217 |
| PubMedSearch : Holmquist_1995_J.Protein.Chem_14_217 |
| PubMedID: 7662109 |
| Gene_locus related to this paper: humla-1lipa |
| Gene_locus related to this paper: humla-1lipa |
Holmquist M, Clausen IG, Patkar S, Svendsen A, Hult K (1995)
Probing a functional role of Glu87 and Trp89 in the lid of Humicola lanuginosa lipase through transesterification reactions in organic solvent
J Protein Chem
14 :217
Holmquist M, Clausen IG, Patkar S, Svendsen A, Hult K (1995)
J Protein Chem
14 :217