Characterization of a novel α-amylase from Lipomyces kononenkoae and expression of its gene (LKA1) in Saccharomyces cerevisiae

Andries J C Steyn, Isak S. Pretorius*

*Corresponding author for this work

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

A highly active α-amylase (76 250 Da) secreted by the raw starch-degrading yeast Lipomyces kononenkoae strain IGC4052B was purified and characterized. Using high performance liquid chromatography (HPLC), end-product analysis indicated that the L. kononenkoae α-amylase acted by endo-hydrolysis on glucose polymers containing α-1,4 and α-1,6 bonds, producing mainly maltose, maltotriose and maltotetraose. The following NH2-terminal amino acids were determined for the purified enzyme: Asp-Cys-Thr-Thr-Val-Thr-Val-Leu-Ser-Ser-Pro-Glu-Ser-Val-Thr-Gly. The L. kononenkoae α-amylase-encoding gene (LKA1), previously cloned as a cDNA fragment, was expressed in Saccharomyces cerevisiae under the control of the PGK1 promoter. The native signal sequence efficiently directed the secretion of the glycosylated protein in S. cerevisiae. De-glycosylation of the enzyme indicated that post-translational glycosylation is different in S. cerevisiae from that in L. kononenkoae. Zymogram analysis indicated that glycosylation of the protein in S. cerevisiae had a negative effect on enzyme activity. Southern-blot analysis revealed that there is only a single LKA1 gene present in the genome of L. kononenkoae.

Original languageEnglish
Pages (from-to)526-533
Number of pages8
JournalCurrent Genetics
Volume28
Issue number6
DOIs
Publication statusPublished - Nov 1995
Externally publishedYes

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