Different ethyl 1-thio-β-D-disaccharides have been synthesised by transgalactosylation using the β-galactosidase from Bacillus circulans as biocatalyst. This β-galactosidase shows mainly a β-1–4 specificity in the galactosyl transfer. Gal-β-(1–4)-O-β-D-GlcSEt 15 was obtained in 36% yield, Gal-β-(1ndash;4)-O-α-D-GlcSEt 19 in 30% yield, Gal-β-(1–4)-O-β-D-GalSEt 17 in 60% yield, Gal-β-(1–4)-O-β-D-GalNAcSEt
已经使用环回芽孢杆菌的
β-半乳糖苷酶作为
生物催化剂,通过反式半
乳糖基化反应合成了不同的乙基1-
硫代-β-D-二糖。这种
β-半乳糖苷酶在半
乳糖基转移中主要表现出β-1–4特异性。GAL-β-(1-4)-O-β-d-Glc
SEt 15以36%的产率得到,GAL-β-(1ndash; 4)-O-α-d-Glc
SEt 19,收率30%,GAL- β-(1-4)-O-β-d-Gal
SEt 17在60%的产率,半
乳糖-β-(1-4)-O-β-d-GalNAc
SEt 20,49%收率,半
乳糖-β-(1 -4)-O-β-d-Gal的-β-(1-4)-O-β-d-GalNAc
SEt 21在9%的产率,半
乳糖-β-(1-6)-O-β-d-Glc
SEt 16在3%的产率和Gal-β-(1-3)-O-β-d-Xyl
SEt 18在25%的产率。