The serine proteases cathepsin G and proteinase 3 in wild-type (+/+) and serglycin knockout mice (−/−) bone marrow cells. (A) Proteinase 3 activity (+/+, n = 3; −/−, n = 6) was measured spectrophotometrically by the degradation rate for methoxysuccinyl-Ala-Ala-Pro-Val-P-nitroanilide. The activity expressed as absorbance change per minute at 405 nm is the activity not inhibitable by SLPI. (B) Cathepsin G activity (+/+, n = 3; −/−, n = 3) was measured spectrophotometrically by dissociation rate for N-succinyl-Ala-Ala-Pro-Phe-P-nitroanilide at 410 nm. No statistically significant differences (5% level, log₁₀-transformed data, independent t test) in serine protease activities could be detected between wild-type and serglycin^−/− bone marrow cells. Median is indicated by bold line and range by whiskers. (C) Western blotting for cathepsin G (CG); MPO is used as an internal loading control. The 2 blots represent the upper and lower part of the same blot cut into 2 before antibody incubation. Molecular weight markers are indicated. (D-E) Immunocytochemistry for cathepsin G on bone marrow cells from wild-type (D) and serglycin^−/− mice (E); bar, 20 μm.