Abstract
YM-47141, a peptidic compound recently isolated from Flexibactor sp. Q17897, strongly inhibited human leukocyte elastase (HLE) with Ki value 2.1 × 10−7 M. Unlike other serine protease inhibitors, YM-47141 exhibited relatively weak effects on cathepsin G and α-chymotrypsin and its inhibitory Ki values were 9.2 × 10−6 M and 1.3 × 10−6 M, respectively. It bad little, or no inhibitory effect on plasmin, thrombin, trypsin and kallikrein (IC50 > 10−4 M). The inhibition of HLE by YM-47141 was reversible and of a mixed type.