Distinct Proteasome Subpopulations in the Alveolar Space of Patients with the Acute Respiratory Distress Syndrome

Table 2

Specific activities of proteasomes isolated from healthy controls and ARDS patients.

	Chtr (pmol/min μg)	Try (pmol/min μg)	PGPH (pmol/min μg)	Chtr/PGPH	PGPH/Try	Chtr/Try
Healthy controls	24.31	0.73	8.22	2.95	11.2	33.3
ARDS patients	9.87	0.68	9.93	0.99	14.6	14.5

Proteolytic activities of purified 20S proteasome from BAL supernatant of healthy controls and of ARDS patients, as measured with specific proteasomal fluorogenic substrates. BAL supernatants were pooled from 5 healthy subjects and from 5 ARDS patients, respectively. The ratio of enzyme activities differs between ARDS patients and healthy subjects, suggesting a rearrangement of proteasomal subunit composition.
PGPH: peptidyl-glutamyl peptide-hydrolysing activity; Try: trypsin-like activity; Chtr: chymotrypsin-like activity.