The Action of α‐Mannosidase from Oerskovia sp. on the Mannose‐Rich O‐Linked Sugar Chains of Glycoproteins

Open Access
Publisher Website
Google Scholar
Abstract
α‐Mannosidase was isolated from the culture liquid of Oerskovia sp. The purified enzyme had a molecular mass of 480 kDa and comprises four identical subunits. The enzyme cleaves bonds in side chains of yeast mannan (Km= 0.08 mM, kcat= 1.02 μmol · min−1· mg−1) and reveals a low activity towards p‐nitrophenyl α‐D‐mannopyranoside. The α‐mannosidase is a Ca2+‐dependent enzyme and is inhibited by EDTA. The enzyme possess no endo‐mannosidase activity releasing only mannose in the reaction with the inversion of anomeric configuration and could be classified as exo‐α‐mannanase. The enzyme revealed a high deglycosylating activity towards the short mannose‐rich O‐linked carbohydrate chains of glycoproteins.