Metabolism of Thienamycin and Related Carbapenem Antibiotics by the Renal Dipeptidase, Dehydropeptidase-I

Abstract

Thienamycin (THM), the N-formimidoyl thienamycin derivative MK0787, and related carbapenem antibiotics were metabolized extensively in mice, rats, rabbits, dogs, rhesus monkeys, and chimpanzees. Urinary recovery of THM ranged from a low of 5% in dogs to 58% in rhesus monkeys. Renal clearance rates in dogs and chimpanzees were unusually low, less than glomerular filtration rates. The reduction in clearance of THM and MK0787 from plasma of rats and rabbits after ligation of renal arteries indicate that the kidneys are responsible for 35 and 92%, respectively, of metabolic drug clearance. Degradation was detected only in kidney homogenates. The enzyme activity was membrane bound and sensitive to inhibitors of Zn-metalloenzymes such as EDTA. A renal dipeptidase, dehydropeptidase-I (DHP-I), EC 3.4.13.11, was found to be responsible for the metabolism of the THM-class antibiotics, which exhibit a structural homology to dehydropeptides. A parallel increase in specific activity against THM and the substrate of DHP-I, glycyldehydrophenylalanine, was observed during solubilization and purification of the enzyme from porcine and human renal cortex. DHP-I was found to catalyze the hydrolysis of the beta-lactam ring in THM and MK0787. The products of the enzyme reaction were identical by high-powered liquid chromatography to their respective metabolites found in the urine. Nonbasic Nacylated THM and natural N-acylated carbapenems (epithienamycins and olivanic acids) were degraded 4-to 50-fold faster than THM when exposed to the enzymatic hydrolysis of DHP-I. Good correlations were obtained between the increased susceptibility of the carbapenem antibiotics to DHP-I as measured in the in vitro enzyme assay and the generally lower recoveries of active antibiotic in the urine of test animals. Despite this unusual degree of metabolism localized in the kidney, the plasma half-life of MK0787 and its efficacy against experimental systemic infections in animals remain satisfactory.Thienamycin (THM) and the N-formimidoyl thienamycin derivative MK0787 are members of a new class of structurally novel beta-lactam antibiotics, the carbapenems. Both are known for their high orders of activity against a broad spectrum of bacteria (11,18,19). Their breadth of activity is in part attributable to resistance to attack by bacterial beta-lactamases (17).The low recovery of unaltered THM and MK0787 in the urine of laboratory animals suggested that these antibiotics are extensively metabolized. Incomplete urinary recoveries of cephalosporins such as cephalothin and cefotaxime have been ascribed to enzymatic (hepatic) cleavage of their acetylated side chains. In both instances, desacetyl metabolites with reduced antimicrobial activity and an intact beta-lactam are recovered in the urine of laboratory animals and in humans (6,7,9,20).Biochemical studies presented in this report show that low urinary recoveries of THM and MK0787 result from the hydrolysis of the betalactam ring by the renal dipeptidase, dehydropeptidase-I

Leukotriene D 4 and cystinyl-bis-glycine metabolism in membrane-bound dipeptidase-deficient mice

“…␤-lactamase activity (a specific measure of MBD activity) was assayed as previously described (34). Activity in homogenates from different tissues from wild-type, heterozygous, and homozygous mice was determined by measuring the rate of hydrolysis of the unsaturated dipeptide glycyldehydrophenylalanine.…”

In vivo efficacy of doripenem (DRPM) against Pseudomonas aeruginosa in murine chronic respiratory tract infection model

“…Araki et al, Page 10 of 14 Carbapenems are hydrolyzed at the β-lactam ring by mammalian DHP-I [12,13].…”

Hydrolysis of S-aryl-cysteinylglycine conjugates catalyzed by porcine kidney cortex membrane dipeptidase

“…MDP, a Zn 2+ -containing enzyme, is inhibited by general metalloenzyme inhibitors such as dithiothreitol (DTT) and also by the specific inhibitor cilastatin Littlewood et al, 1989). Renal MDP has been shown to catalyze the degradation of β-lactam carbapenem antibiotics such as imipenem (Kropp et al, 1982). Consequently, coadministration of cilastatin is used to improve the therapeutic effectiveness of these agents by extending their half-life.…”

“…The relative roles of these enzymes in the metabolism of xenobiotics are still unclear. Kropp et al, 1982;3, Farrell et al, 1987;4, Hirota et al, 1987;5, Hooper et al, 1987;6, Campbell et al, 1988;7, Adachi et al, 1989;8, Littlewood et al, 1989;9, Satoh et al, 1993;10, Rankin et al, 1980;11, Hussain et al, 1981;12, McIntyre and Curthoys, 1982;13, Hirota et al, 1985;14, Vanderheyden et al, 2006;15, Teufel et al, 2003;16, Kaur et al, 2009;17, Jösch et al, 1998;18, Jösch et al, 2003;19, Cappiello et al, 2004;20, Turzynski and Mentlein, 1990;21, Mathew et al, 2000;22, Suzuki et al, 2001.…”