A multifunctional sialyltransferase has been cloned from Pasteurella multocida strain P-1059 and expressed in E. coli as a truncated C-terminal His6-tagged recombinant protein (tPm0188Ph). Biochemical studies indicate that the obtained protein is (1) an alpha2,3-sialyltransferase (main function), (2) an alpha2,6-sialyltransferase, (3) an alpha2,3-sialidase, and (4) an alpha2,3-trans-sialidase. The recombinant tPm0188Ph is a powerful tool in the synthesis of structurally diverse sialoside libraries due to its relaxed substrate specificity, high solubility, high expression level, and multifunctionality.

In this report a recombinant bifunctional phosphomannose isomerase/GDP-D-mannose pyrophosphorylase from Helicobacter pylori has been studied. The enzyme catalyzes the first and third steps of GDP-D-mannose biosynthesis from D-fructose-6-phosphate. The first step, isomerization from D-fructose-6-phosphate to D-mannose-6-phosphate, is found to be rate-limiting in GDP-D-mannose biosynthesis due to feedback inhibition. The inhibition is of non-competitive (mixed) type. As the enzyme is found only in bacteria probably participating in capsular polysaccharide biosynthesis, it could be a specific therapeutic target against bacterial infection. ß 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

Glucuronide prodrugs have shown promising efficacy in anti-cancer therapy due to their increased specificity and reduced systemic toxicity. The prodrugs can be used in prodrug monotherapy (PMT), which is based on elevated tumor beta-glucuronidase activity. beta-Glucuronidase activates the low-toxic prodrugs into highly cytotoxic agents specifically in the tumor site. The specificity of the prodrugs can be further improved by combined use with monoclonal antibodies against tumor-specific antigens, namely antibody-directed enzyme prodrug therapy (ADEPT); and the potency of the prodrugs can be greatly enhanced with the incorporation of an appropriate radionuclide in the combined chemo- and radio-therapy of cancer (CCRTC) strategy. The prodrugs can also be utilized to modify liposomes for efficient delivery of anti-cancer drugs.

No abstract

[reaction: see text] Enzymatic production of glycoconjugates is hampered by expensive phosphagens such as acetyl phosphate (AcP) and phosphoenolpyruvate (PEP). Here, we introduce creatine phosphate--creatine kinase system as a novel and practical energy source in carbohydrate synthesis. This system was successfully demonstrated in the production of bioactive oligosaccharides with different sugar nucleotide regeneration systems.