Enzymatic synthesis of a new inhibitor of α-amylases: acarviosinyl-isomaltosyl-spiro-thiohydantoin Original Research Article

Synthesis of acarviosinyl-isomaltosyl-spiro-thiohydantoin in yields up to 20%, has been achieved by Bacillus stearothermophilus maltogenic amylase (BSMA). BSMA is capable of transferring the acarviosine–glucose residue from an acarbose donor onto glucopyranosylidene-spiro-thiohydantoin. Reactions were followed using HPLC and MALDI-TOF MS. 1H and 13C NMR studies revealed that the enzyme reserved its stereoselectivity. Glycosylation took place mainly at C-6 resulting in α-acarviosinyl-(1→4)-α-d-glucopyranosyl-(1→6)-d-glucopyranosylidene-spiro-thiohydantoin. This compound was found to be a much more efficient salivary amylase inhibitor than glucopyranosylidene-spiro-thiohydantoin with kinetic constants of KEI = 0.19 μM and KESI = 0.24 μM.