• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.188-190
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• 1998

Penicillide, having a 5H, 7H-dibenzo［b,g］［1,5］ dioxocin-5-one skeleton, was isolated from the culture broth of Penicillium sp. F60760 as a nonpeptide inhibitor of calpain, a calcium-activated papain-like protease. The $IC_50$ value for the effect of penicillide against m-calpaln was $7.1{\mu}M$. However, penicillide did not inhibit papain at a concentration of $200{\mu}M$. These results suggest that penicillide is a new class of nonpeptide calpain inhibitor having an eight membered lactone ring.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.291-292
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• 2009

• Journal of Life Science
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• v.20 no.6
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• pp.831-837
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• 2010

KR-31125 (2-butyl-5-dimethoxymethyl-6-phenyl-7-methyl-3-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-3H-imidazo[4,5-b]pyridine) is a potent inhibitor of angiotensin II type 1 ($AT_1$) receptors in human recombinant $AT_1$ receptors and rabbit aorta. These in vitro studies revealed that KR-31125 inhibited specific [$^{125}I$] [$Sar^1$, $Ile^8$]-angiotensin II binding to human recombinant $AT_1$ receptors in a concentration dependent manner with an $IC_{50}$ value of $19.72{\pm}2.65$ nM. However, no interaction with $AT_2$ receptors was detected as displayed by the competition binding of [$^{125}I$] CGP 42112A to human recombinant $AT_2$ receptor. The binding action was also confirmed as a competitive mode that was identical to the previously studied compound, losartan. In addition, KR-31125 caused a nonparallel shift to the right in the concentration response curves to angiotensin II with a 30-80% decrease in the maximum contractile responses ($pK_B$: 7.63). Compared to the previous studies with losartan that showed a parallel right shift in the maximum contractile responses to AII ($pA_2$: 7.59), KR-31125 presented a different mode of action with a similar potency to losartan. These results demonstrate that KR-31125 is a highly potent and $AT_1$ selective angiotensin II receptor antagonist that can be applied to the fields of new diagnostic and research tools with upcoming in vivo study results.