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Biomedical subjects

M A Ondetti

Publications and source records attributed to M A Ondetti.

At least 37 records · Page 2Linked to original sources
PubMed1979

Design of potent and specific inhibitors of carboxypeptidases A and B.

The combination in one molecule of functional groups that can interact specifically with different substrate binding areas at the active site of carboxypeptidases A and B has led to the development of potent and specific inhibitors of these enzymes. 2-Benzyl-3-mercaptopropanoic acid (SQ 14,603) has a Ki of 1.1 x 10(-8) M vs. carboxypeptidase A and a Ki of 1.6 x 10(-4) M vs. the B enzyme. 2-Mercaptomethyl-5-guanidinopentanoic acid (SQ 24,798) has a Ki of 4 x 10(-10) M vs. carboxypeptidase B and a Ki of 1.2 x 10(-5) M vs. carboxypeptidase A. It is proposed that the sulfhydryl groups of these inhibitors bind to the catalytically important zinc ions of these enzymes, and that, in conjunction with the benzyl and guanidinopropyl side chains, they are responsible for their specificity.

3-Mercaptopropionic Acid↗
PubMed1978

Diastereomeric 7-ureidoacetyl cephalosporins. II. 7beta [[[(Aminocarbonyl) amino]-2-thienylacetyl] amino]-7-methoxy-3-[[(1-methyl-1H-tetrazol-5-yl) thio] methyl]-8-oxo-5-thia-1-azabicyclo [4.2.0] oct-2-ene-2-carboxylic acid.

The synthesis and antibacterial activity in vitro of 7-methoxylated cephalosporins having a thienylureidoacetyl or a thienylglycyl C-7 side-chain are described. Acylation of 7 beta-amino-7-methoxycephems with a novel 2-aminooxazolone hydrochloride under neutral conditions gave the thienylureidoacetyl derivatives in good yield with retention of configuration. 7 beta-[[D-[(Aminocarbonyl)amino]-2-thienylacetyl]amino]-7-methoxy-3-[[(1-methyl-1H-tetrazol-5-yl)thio] methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt (SQ 14,359) was found to have a broad-spectrum of antibacterial activity in vitro, particularly against beta-lactamase-producing organisms.

Bacteria↗
PubMed1977

Design of specific inhibitors of angiotensin-converting enzyme: new class of orally active antihypertensive agents.

A hypothetical model of the active site of angiotensin-converting enzyme, based on known chemical and kinetic properties of the enzyme, has enabled us to design a new class of potent and specific inhibitors. These compounds, carboxyalkanoyl and mercaptoalkanoyl derivatives of proline, inhibit the contractile response of guinea pig ileal strip to angiotensin I and augment its response to bradykinin. When administered orally to rats, these agents inhibit the pressor effect of angiotensin I, augment the vasodepressor effect of bradykinin, and lower blood pressure in a model of renovascular hypertension.

Administration, Oral↗
PubMed1975

Bradykinin analogs containing beta-homoamino acids.

Two new analogs of bradykinin, [8-beta-homophenylalanine]- and [7-beta-homoproline]bradykinin, have been synthesized by the solid-phase technique. In the anesthetized rat, [7-beta-HPro]bradykinin was equipotent with bradykinin and 30-100 times more potent than [8-beta-HPhe]bradykinin in vasodepressor activity. Both analogs were resistant to degradation in vitro by dipeptidylcarboxypeptidase from rabbit lung. Only the 7-beta-HPro analog seemed to be resistant to this type of degradation in vivo, since its hypotensive effect in the anesthetized rat was not potentiated by SQ 20881 (BPP9a), an inhibitor of dipeptidylcarboxypeptidase.

Amino Acids↗
PubMed1975

Action of cholecystokinin and cholinergic agents on calcium transport in isolated pancreatic acinar cells.

COOH-terminal octapeptide of cholecystokinin (CCK-octapeptide) and the cholinergic agent carbamylcholine each produced a fourfold stimulation of calcium outflux in guinea pig isolated pancreatic acinar cells. Neither agent altered calcium influx. Stimulation of calcium outflux was rapid and specific, was abolished by reducing the incubation temperature to 4 degrees C, and was a saturable function of the secretagogue concentration. The concentrations of CCK-octapeptide and carbamylcholine that produced half-maximal stimulation of calcium outflux were 3.1 x 10(-10) M and 4.9 x 10(-5) M, respectively. The cholinergic antagonist antropine competitively inhibited carbamylcholine stimulation of calcium outflux but did not alter stimulation produced by CCK-octapeptide. Stimulation of calcium outflux by maximal concentrations of carbamycholine plus CCK-octapeptide was the same as that produced by a maximal concentration of either agent alone.Calcium outflux became refractory to stimulation by secretagogues, and incubation with either CCK-ostapeptide or carbamylcholine produced a refractoriness to both agents. The relative potencies with CCK and its related fragments stimulated calcium outflux were CCK-octapeptide greater than heptapeptide greater than CCK greater than hexapeptide = gastrin. Secretin, glucagon, and vasoactive intestinal peptide, at concentrations as high as 10(-5) M, failed to alter calcium outflux and did not affect stimulation by CCK-octapeptide or by carbamycholine.

Amylases↗