The Donor Substrate Spectrum of Recombinant Sucrose Synthase 1 from Potato for the Synthesis of Sucrose Analogues

Abstract

Abstract The donor substrate spectrum of recombinant sucrose synthase 1 (SuSy1) from potato was studied in order to synthesise novel sucrose analogues. With D ‐fructose as acceptor substrate SuSy1 accepts a variety of UDP‐activated sugars, e.g., UDP‐ N ‐acetyl‐α‐ D ‐glucosamine (UDP‐GlcNAc, 2 ) (100%), UDP‐α‐ D ‐glucuronic acid (UDP‐GlcA, 3 ) (32%), UDP‐α‐ D ‐xylose (UDP‐Xyl, 4) (39%), UDP‐α‐ D ‐galactose (UDP‐Gal, 5) (23%), and UDP‐ N ‐acetyl‐α‐ D ‐galactosamine (UDP‐GalNAc, 6) (23%). The kinetic analyses revealed that the non‐natural donors 2 (k cat /K m 1.2 s −1 mM −1 ) and 5 (k cat /K m 0.01 s −1 mM −1 ) were relative poor substrates compared to UDP‐Glc 1 (k cat /K m 310.4 s −1 mM −1 ). UDP‐GlcNAc was used in a preparative synthesis to produce 188 mg (0.5 mmol) 2‐acetamido‐2‐deoxy‐ D ‐glucopyranosyl‐β‐ D ‐fructofuranoside ( 9 ). The sucrose analogue 9 was not hydrolysed by invertase.