Protein degradation under plasma treatment conditions were investigated using Ni-NTA agarose, to which enzyme is bound non-covalently. Proteins VCPO, LdhA, LacZ, or GapA were immobilized on Ni-NTA agarose and treated with plasma or left untreated. Using ninhydrin, after plasma treatment times of up to 600 s, the concentration of terminal amino groups as an indicator of protein degradation was determined for free enzyme and enzyme immobilized on Ni-NTA agarose. Means and standard deviations of three independent biological replicates are shown.