Fig. 3.

Inhibition of NE with mixtures of pure A2M and pure M variant A1AT in concentrations equivalent to those found in serum from various A1AT genotypes. Inhibition assays of NE using purified inhibitors in concentrations equivalent to those found in PiMM, PiFZ, and PiZZ sera, with SlaaapN as the substrate. The results show that altering the relative concentrations of pure A1AT and pure A2M produces a similar effect to that observed with serum samples, with the greatest residual NE activity being observed when inhibitors are used in proportions equivalent to PiZZ serum. The reduced concentration of A1AT relative to A2M (as found with mutant A1AT variants) results in greater residual NE activity when the A1AT is in a molar excess of NE, suggesting greater partitioning of NE to A2M where the enzyme remains active. Pure A1AT alone (square points) is capable of completely inhibiting NE activity. The SE is small and falls within the symbol.