Changes in human plasma α-D-mannosidase activity during pregnancy

Abstract There are significant and progressive increases in plasma acidic (pH optimum 4.2) and intermediate (pH optimum 5.6) α-mannosidase during pregnancy. The acidic α-mannosidase in plasma from pregnant women binds to concanavalin A and has the same apparent molecular weight as the acidic α-mannosidase in control plasma. The 2–3-fold increase in acidic α-mannosidase in pregnancy is due to an increase in the most negatively charged form of acidic α-mannosidase, B 2 , which is slightly more negatively charged than its counterpart in the control plasma. The intermediate α-mannosidase, which increases by approximately 50% during pregnancy, can be resolved by a combination of chromatography on concanavalin A and gel filtration into the same forms found in control plasma.