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Table 1 Activity of r-α1-PI from E. coli and A. niger and evaluation of molecular weight of recombinant and plasma-derived species determined by MALDI-MS

From: Expression of human α1-proteinase inhibitor in Aspergillus niger

Protein Activitya (%) Molecular massb
pd-α1-PI (standard) 100 50,300
degly-pd-α1-PI n.a.c 44,210
r-α1-PI/E. coli 35d 45,000e
r-α1-PI/A. niger 76f,g 50,100
  1. aThe calculations were based on comparison with pdtαxtPI as a standard (100%) and using normalized equal concentrations of r-α1-PI samples as determined by ELISA; bmolecular weight is shown as a an average value measured for 2 samples; c not available; pd-α1-PI was enzymatically deglycosylated under denaturing conditions; d as measured for His-tagged r-α1-PI within 1.5 h after elution from the TALON beads; e as estimated by amino acid sequence for α1-PI without glycans; f shown for A. niger supernatant after Amicon 10 K filtration procedure; g the standard deviation of our potency assay is ± 15%.