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Human carboxymethylenebutenolidase as a bioactivating hydrolase of olmesartan medoxomil in liver and intestine.

ABSTRACT: Olmesartan medoxomil (OM) is a prodrug type angiotensin II type 1 receptor antagonist widely prescribed as an antihypertensive agent. Herein, we describe the identification and characterization of the OM bioactivating enzyme that hydrolyzes the prodrug and converts to its pharmacologically active metabolite olmesartan in human liver and intestine. The protein was purified from human liver cytosol by successive column chromatography and was identified by mass spectrometry to be a carboxymethylenebutenolidase (CMBL) homolog. Human CMBL, whose endogenous function has still not been reported, is a human homolog of Pseudomonas dienelactone hydrolase involved in the bacterial halocatechol degradation pathway. The ubiquitous expression of human CMBL gene transcript in various tissues was observed. The recombinant human CMBL expressed in mammalian cells was clearly shown to activate OM. By comparing the enzyme kinetics and chemical inhibition properties between the recombinant protein and human tissue preparations, CMBL was demonstrated to be the primary OM bioactivating enzyme in the liver and intestine. The recombinant CMBL also converted other prodrugs having the same ester structure as OM, faropenem medoxomil and lenampicillin, to their active metabolites. CMBL exhibited a unique sensitivity to chemical inhibitors, thus, being distinguishable from other known esterases. Site-directed mutagenesis on the putative active residue Cys(132) of the recombinant CMBL caused a drastic reduction of the OM-hydrolyzing activity. We report for the first time that CMBL serves as a key enzyme in the bioactivation of OM, hydrolyzing the ester bond of the prodrug type xenobiotics.

SUBMITTER: Ishizuka T

PROVIDER: S-EPMC2852926 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Human carboxymethylenebutenolidase as a bioactivating hydrolase of olmesartan medoxomil in liver and intestine.

Ishizuka Tomoko T Fujimori Izumi I Kato Mitsunori M Noji-Sakikawa Chisa C Saito Motoko M Yoshigae Yasushi Y Kubota Kazuishi K Kurihara Atsushi A Izumi Takashi T Ikeda Toshihiko T Okazaki Osamu O

The Journal of biological chemistry 20100219 16

Olmesartan medoxomil (OM) is a prodrug type angiotensin II type 1 receptor antagonist widely prescribed as an antihypertensive agent. Herein, we describe the identification and characterization of the OM bioactivating enzyme that hydrolyzes the prodrug and converts to its pharmacologically active metabolite olmesartan in human liver and intestine. The protein was purified from human liver cytosol by successive column chromatography and was identified by mass spectrometry to be a carboxymethylene ...[more]

PMID: 20177059

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Project description:This study was to evaluate the efficacy and safety of triple fixed-dose combination (FDC) therapy with olmesartan medoxomil (OM) 20 mg, amlodipine (AML) 5 mg, and hydrochlorothiazide (HCTZ) 12.5 mg (OM/AML/HCTZ 20/5/12.5) in Korean patients with moderate hypertension not controlled with dual FDC therapy (OM/HCTZ 20/12.5).In this multicenter, randomized, double-blind, parallel-group study, Korean patients aged 20 to 75 years with stage 2 hypertension who had a mean seated diastolic blood pressure (msDBP) ?100 mmHg were enrolled when their BP was uncontrolled [mean seated systolic BP (msSBP)/msDBP >140/90 mmHg or msSBP/msDBP >130/80 mmHg with diabetes or chronic kidney disease] with 4-week dual FDC therapy (OM/HCTZ 20/12.5). The patients were randomized to receive either OM/AML/HCTZ 20/5/12.5 or OM/HCTZ 20/12.5 once daily for 8 weeks. At the end of 8 weeks, patients with uncontrolled BP were assigned to receive either OM/AML/HCTZ 40/5/12.5 or OM/AML/HCTZ 20/5/12.5 in an additional 8-week open-label extension period.A total of 623 patients received a 4-week run-in treatment with OM/HCTZ, 341 patients were randomized, and finally, 167 patients in the OM/AML/HCTZ group and 171 patients in the OM/HCTZ group were analyzed for the full analysis set. Non-responders after the 8 weeks of double-blind treatment continued the 8-week open-label treatment with OM/AML/HCTZ 40/5/12.5 mg (n = 32) or OM/AML/HCTZ 20/5/12.5 mg (n = 71). After 8 weeks of double-blind treatment, the changes in msDBP were -9.50 (8.46) mmHg in the OM/AML/HCTZ group and -4.23 (7.41) mmHg in the OM/HCTZ group (both p < 0.0001 vs. baseline; p < 0.0001 between groups). The response rates for both msSBP and msDBP at week 8 were 65.27 % in the OM/AML/HCTZ group and 37.43 % in the OM/HCTZ group (p < 0.0001 between groups). The response rates for both msSBP and msDBP at week 16 after open-label treatment were 18.75 % in the OM/AML/HCTZ 40/5/12.5 group and 46.48 % in the OM/AML/HCTZ 20/5/12.5 group (p = 0.0073 between groups). All medications were well tolerated.In Korean patients with moderate hypertension not controlled with dual FDC therapy (OM/HCTZ 20/12.5) as first-line therapy, switching to triple FDC therapy (OM/AML/HCTZ 20/5/12.5) was associated with significant BP reductions and greater achievement of BP goals, and was well tolerated (ClinicalTrials.gov Identifier: NCT01838850).

Dataset Information

Human carboxymethylenebutenolidase as a bioactivating hydrolase of olmesartan medoxomil in liver and intestine.

Publications

Human carboxymethylenebutenolidase as a bioactivating hydrolase of olmesartan medoxomil in liver and intestine.

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