Rat Brain α‐Mannosidase: Purification, Properties, and Interaction with Its Antibodies

Abstract
.alpha.-D-Mannosidase (EC 3.2.1.24) was purified to homogeneity from adult rat brain. The enzyme, of apparent MW 397,000, appears to be formed of subunits of MW 120,000 made of 2 protomers (62,000) bound by disulfide bridges. Isoelectric focusing gives 2 bands, of pI [isoelectric point] 5.40 and 5.15. Both isoenzymes seem to have the same pH curve (a small peak of activity at pH 4.5 and a maximum of activity around pH 6.0). These 2 isoenzymes are immunologically related.