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Biomedical subjects

M E Ellis

Publications and source records attributed to M E Ellis.

96 records · Page 6Linked to original sources

Synthesis and biological activity of a ketomethylene analogue of a tripeptide inhibitor of angiotensin converting enzyme.

An analogue of a tripeptide inhibitor of angiotensin converting enzyme, Bz-Phe-Gly-Pro, has been synthesized in which the amide bond connecting phenylalanine and glycine has been replaced by a ketomethylene group. This nonpeptide analogue, 20, shows more potent converting enzyme inhibiting activity, I50 = 0.07 microM, than Bz-Phe-Gly-Pro, I50 = 9.4 microM, or than the orally active D-3-mercapto-2-methylpropanoyl-L-proline (captopril, 1), I50 = 0.30 microM. Compound 20 has a Ki of 1.06 X 10(-7) and either competitive or noncompetitive enzyme kinetics depending on what substrate is used in the converting enzyme assay. In tests for inhibition of angiotensin I induced contractions in the guinea pig ileum, 20 has one-tenth the activity of 1.

Angiotensin I↗

Alpha-adrenergic regulation of the secretion of an anticomplementary factor in mouse saliva.

Mouse saliva contains a potent inhibitor of complement activity. The secretion of this inhibitor appears to be regulated by action on alpha-adrenergic receptors for two reasons. First, an alpha-agonist (norepinephrine) elicited saliva with a 260-fold higher specific activity of the inhibitor than that obtained with a cholinergic agent (pilocarpine). Second, the alpha-agonist elicited saliva having 43-foldgreater specific activity than that obtained following administration of a beta-adrenergic agonist (isoproterenol). This anticomplementary factor probably proteolytically degrades one or more of the complement components since it is inhibited by several protease inhibitors. The salivary anticomplementary factor is more potent than trypsin, chymotrypsin, thrombin, or Kallikrein. The anticomplementary factor has a pattern of inhibition like that of Kallikrein but unlike those of trypsin or chymotrypsin.

Animals↗