Residual activity of VCPO, LdhA, LacZ, or GapA reversibly immobilized on Ni-NTA agarose after 300 s of plasma treatment. After plasma treatment, enzyme was eluted from the carrier with imidazole and washed with buffer. Protein concentration was determined using Bradford assay. Enzyme activity was measured using 5 µl of the eluted enzyme in its respective activity assay. Activities were normalized to the respective protein concentrations and activity of the untreated enzyme was set to 100%. Means and standard deviations represent three independent biological replicates.