J. Gasperik et E. Hostinova, GLUCOAMYLASES ENCODED BY VARIANT SACCHAROMYCOPSIS-FIBULIGERA GENES - STRUCTURE AND PROPERTIES, Current microbiology, 27(1), 1993, pp. 11-14
The genes of two variant glucoamylases (GLA1 and GLU1) of Saccharomyco
psis fibuligera were expressed in Saccharomyces cerevisiae, and bioche
mical properties of the secreted enzymes were compared. It was found t
hat three amino acid alterations in the signal peptide and N-terminal
regions of the variants had no effect on the levels of the secreted en
zymes. Amino acid alterations in the C-terminal region of the mature p
roteins influenced their specific activity, substrate specificity, as
well as temperature and pH optima. Because of the glycosylation hetero
geneity, the glucoamylases of each gene variant were isolated and puri
fied in two forms (A and B), which were essentially similar in catalyt
ic and physicochemical properties but differed in their thermal stabil
ity and ability to renaturate after thermal denaturation.