Elling L, Grothus M, Kula M R
Institut für Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Jülich, FRG.
Glycobiology. 1993 Aug;3(4):349-55. doi: 10.1093/glycob/3.4.349.
The unique character of the plant glucosyltransferase sucrose synthase, to catalyse in vitro the synthesis and cleavage of sucrose under appropriate conditions, can be exploited for the enzymatic synthesis of carbohydrates. The present paper describes the potential utilization of sucrose synthase from rice for the enzymatic synthesis of activated sugars and saccharides. In the cleavage reaction of sucrose, the nucleoside diphosphates can be used in the order UDP > TDP > ADP > CDP > GDP to obtain the corresponding activated glucoses. In batch reactions, > 90% conversion of UDP and TDP could be achieved. Substituting different di- and trisaccharides for sucrose in the cleavage reaction with UDP 2-deoxysucrose was the most promising substrate. Sucrose synthase was combined with UDP-galactose 4'-epimerase and beta 1-4 galactosyltransferase to synthesize N-acetyllactosamine with in situ regeneration of UDP-glucose. In the synthesis reaction of sucrose synthase, different donor (UDP-sugars) and acceptor substrates were investigated. UDP-N-acetylglucosamine and UDP-xylose could be used in combination with fructose as acceptor. D-Xylulose, D-tagatose, D-lyxose, D-psicose, L-sorbose, D-mannose, L-arabinose, 1,6 anhydroglucose, lactulose, raffinose and isomaltulose can serve as acceptors for UDP-glucose.
植物葡萄糖基转移酶蔗糖合酶具有独特的特性，即在适当条件下可在体外催化蔗糖的合成与裂解，这一特性可用于碳水化合物的酶促合成。本文描述了水稻蔗糖合酶在活性糖和糖类酶促合成中的潜在应用。在蔗糖的裂解反应中，核苷二磷酸按UDP > TDP > ADP > CDP > GDP的顺序使用，以获得相应的活性葡萄糖。在分批反应中，UDP和TDP的转化率可达到90%以上。在与UDP的裂解反应中，用不同的二糖和三糖替代蔗糖，2-脱氧蔗糖是最有前景的底物。蔗糖合酶与UDP-半乳糖4'-表异构酶和β1-4半乳糖基转移酶结合，原位再生UDP-葡萄糖以合成N-乙酰乳糖胺。在蔗糖合酶的合成反应中，研究了不同的供体（UDP-糖）和受体底物。UDP-N-乙酰葡糖胺和UDP-木糖可与果糖结合用作受体。D-木酮糖、D-塔格糖、D-来苏糖、D-阿洛酮糖、L-山梨糖、D-甘露糖、L-阿拉伯糖、1,6-脱水葡萄糖、乳果糖、棉子糖和异麦芽糖可作为UDP-葡萄糖的受体。
