Principal characteristics of α‐galactosidase from Leuconostoc mesenteroides subsp. mesenteroides

Abstract

α‐Galactosidases (α‐gal) from six strains of Leuconostoc mesenteroides subsp. mesenteroides, which were isolated from four different ecological niches, have been characterized. The enzymes have an optimum pH ranging from 5.5 to 6.4. Strain 19A possesses a pH optimum close to neutral. The optimum temperature varied with the strains, ranging from 37 to 43 °C. The Km values of the enzymes for substrate p‐nitrophenyl‐α‐D‐galactopyranoside (PNPG) varied from 2.15 to 22.70 mM. α‐Gal from strain 23A had the lowest affinity for substrate PNPG. An increase of the affinity for PNPG in the presence of 10 mM lactose was observed for strains 6M, 19A, 23A, 19M, while this higher affinity for PNPG was also observed in the presence of 10 mM galactose for strains 6M, 23A, 19M. The activation energy of the enzyme from different strains was calculated to be about 62.9–72.8 kJ/mol. Ca2+ ions have a strong inhibitive effect on the enzyme activity. Appearance of α‐gal activity band and protein profiles under the same conditions of SDS‐PAGE allowed an estimation of the apparent molecular weight of α‐gal to be at about 175,000.

Leuconostoc, characteristics, use in dairy technology and prospects in functional foods

“…Despite the ability of Leuconostoc to ferment a-galactosides (Boquien, Desmazeaud, & Corrieu, 1989;Pr! evost et al, 1993;Huang, Pr! evost, & Divi" es, 1994) and the proposal to use a-galactosidase from Ln.…”

“…evost, & Divi" es, 1994) and the proposal to use a-galactosidase from Ln. mesenteroides as a biotechnological approach to remove a-galactosides, attempts did not come out (Huang et al, 1994).…”