Distinct Proteasome Subpopulations in the Alveolar Space of Patients with the Acute Respiratory Distress Syndrome
Figure 5
Subtype pattern of the extracellular alveolar proteasome of patients with ARDS (continuous line) and of plasma from healthy subjects (white points). (a) 20 μg of 20S proteasome from pooled BAL supernatant of five ARDS patients were purified, subjected to chromatography on Mini Q, and separated into their subtypes by elution with increasing concentrations of NaCl. Subtypes detected by absorption at 280 nm are designated by roman figures (I–VII) according to the order of their elution from the column. All subtypes elute at NaCl concentrations (dashed line) between 330 and 370 mmolNaCl/L, and only this detail of the chromatograms is shown. (b) All collected fractions of the subtype pattern chromatography of the extracellular alveolar proteasome of patients with ARDS were measured by the highly specific proteasomal fluorogenic peptides Suc-LLVY-AMC (open points), BZ-VGR-AMC (black rectangle), and Suc-LLE-AMC (Z-LLE-AMC) (open triangle). Only in the fractions 28–30, proteasomal enzyme activity could be observed. Analysis of alveolar proteasome revealed a new proteasomal subtype pattern in the extracellular alveolar space of ARDS patients that differs from that of healthy subjects’ plasma, suggesting that the extracellular alveolar proteasome in ARDS does not derive from plasma.
