Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of enol HIV-1 protease inhibitors which show competitive inhibition and the structure-activity relationship study which led to the design of these compounds are reported. By systematically modifying simple amino acids, Boc-Phe enol and Boc-Tyr enol derivatives yield nanomolar Kiapp values (Kiapp = 0.485 microM and Kiapp = 0.425 microM, respectively). These enols are of low molecular weight (< 500 g/mol) and of non-peptidic nature. The enols are synthesized in a one step chemical synthesis and modifications to increase their potency could easily be performed. Boc-Phe enol and Boc-Tyr enol showed low inhibitory effect on pepsin, Kiapps of 23 and 149 microM, respectively, and Boc-Phe enol showed a Kiapp of 20 microM for cathepsin D. Neither of these two compounds inhibited renin (< 10% inhibition at 200 microM).
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PMID:Synthesis of novel inhibitors of the HIV-1 protease: difunctional enols of simple N-protected amino acids. 792 46

Systematic replacement of the P4-P2 subsites of substrate-based human immunodeficiency virus type 1 protease (HIV-1 PR) inhibitors containing cyclohexylalanylalanine hydroxyethylene dipeptide isostere (Cha-psi [H.E.]-Ala) at positions corresponding to the scissile sites of substrates was carried out. The structure-activity relationship revealed that compounds with the combination of hydrophilic P3 and beta-branched hydrophobic P2 amino acids generally showed strong inhibitory activity against HIV-1 PR. In particular, compounds 4 (Boc-Orn-Val-Cha-psi [H.E.]-Ala-NHBun; Bu(n) = n-butyl, Ki = 11 nM) and 6 (Z-Orn-Val-Cha-psi [H.E.]-Ala-NHBun, Ki = 8 nM) exhibited good enzyme selectivity, possessing no significant inhibitory activities toward closely related aspartic proteases, pepsin, cathepsin D, and renin. As a possible model system for (anti-Mo-MSV/MLV complex (Mo-MSV = Moloney murine sarcoma virus; MLV = murine leukemia virus)) activity was investigated. Both compounds were found to inhibit moderately the focus formation of Mo-MSV/MLV complex in NIH3T3 cells (compound 4, IC50 = 1.8 microM; compound 6, IC50 = 1.0 microM).
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PMID:Studies of human immunodeficiency virus type 1 (HIV-1) protease inhibitors. III. Structure-activity relationship of HIV-1 protease inhibitors containing cyclohexylalanylalanine hydroxyethylene dipeptide isostere. 800 98

Amyloid beta (A beta) is a 39-43-residue protein that originates from proteolysis of the beta-protein precursor (beta PP) and accumulates in senile plaques in brains of Alzheimer's disease (AD) patients. Mutant beta PP, which incorporates an AD-causing double mutation at positions 687-688, has been shown to enhance A beta production in transfected cells. In this work we investigate the susceptibility of the mutant beta PP sequence to proteolytic cleavage by proteinases from human brain. Internally quenched fluorogenic substrates were used that encompass the NH2-terminal sequence of A beta from wild-type beta PP, the double mutant, and the two single substitutions. Proteinase activity in brain extract cleaved the mutant substrate 100-fold faster than the wild-type substrate and the partial mutants 25-fold faster. The major cleavage site in all substrates was at the amyloidogenic Asp1 site. The brain activity appeared to be cathepsin D (CD), as indicated by similarities to purified CD in 1) the rate and site of substrates cleavage, 2) the pH optima, and 3) the sensitivity to pepstatin A. The increased activity against the mutant substrate was not shared by cathepsins B and C, pepsin, HIV proteinase, and Candida albicans Asp-proteinase. Furthermore, CD cleaved a substrate that incorporates the COOH terminus of A beta at positions equivalent to Thr43 and Ala42, at ratios of 68% and 32%, respectively. CD degraded A beta 1-40 into six fragments but A beta 1-42 was completely resistant to digestion, probably because of its aggregation characteristics. These results indicate that CD is capable of producing the cleavages resulting in A beta production and that it may prove to be a suitable therapeutic target.
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PMID:Cleavage at the amino and carboxyl termini of Alzheimer's amyloid-beta by cathepsin D. 803 90

In order to find new effective HIV protease inhibitors, two diterpenes (carnosic acid [1] and carnosol [5]) were isolated from rosemary (Rosmarinus officinalis L.), and rosmanol [2] and semisynthetic derivatives (7-O-methylrosmanol [3], 7-O-ethylrosmanol [4], and 11,12-O,O-dimethylcarnosol [6]) were prepared. The inhibitory activity of all six compounds against HIV-1 protease was tested. The carnosic acid [1] showed the strongest inhibitory effect (IC90 = 0.08 micrograms/ml). The same compound was also assayed against HIV-1 virus replication (IC90 = 0.32 micrograms/ml). The cytotoxic TC90 on H9 lymphocytes was 0.36 micrograms/ml, which is very close to the effective antiviral dose. Additionally, the tested compounds did not inhibit cellular aspartic proteases cathepsin D and pepsin at the concentration range up to 10 micrograms/ml [corrected].
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PMID:Inhibitory effect of carnosic acid on HIV-1 protease in cell-free assays [corrected]. 822 21

CGP 53437 is a peptidomimetic inhibitor of human immunodeficiency virus type 1 (HIV-1) protease containing a hydroxyethylene isostere. The compound inhibited recombinant HIV-1 protease with a Ki of 0.2 nM. The inhibition constant versus human cathepsin D and human cathepsin E was 4 nM. Human pepsin and gastricsin were inhibited with Kis of 8 and 500 nM, respectively, and human renin was inhibited with a Ki of 190 microM. The replication of HIV-1/LAV, HIV-1/Z-84, and HIV-1/pLAI was inhibited with a 90% effective dose of 0.1 microM in acutely infected MT-2 cells. The 50% cytotoxic dose was 100 microM. Similar antiviral activity was observed when the compound was added up to 10 h after infection. At the effective concentration, processing of Gag precursor protein p55 was greatly reduced, confirming an action on the late stage of the virus life cycle, as expected. The efficacy of the inhibitor was also demonstrated by using primary human peripheral blood lymphocytes infected with the HIV-1/LAV strain, low-passage clinical isolates obtained from HIV-1-seropositive individuals (including a zidovudine-resistant strain), and HIV-2/ROD. In these cells, CGP 53437 delayed the onset of HIV replication in a dose-dependent fashion (substantial effects with concentrations of > or = 0.1 microM) as long as the inhibitor was maintained in the culture. CGP 53437 was orally bioavailable in mice. Concentrations in plasma 10-fold in excess of the in vitro antiviral 90% effective dose could be sustained for several hours after oral application of 120 mg/kg. Therefore, CGP 53437 has the potential to be a therapeutically useful anti-HIV agent for the treatment of AIDS.
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PMID:CGP 53437, an orally bioavailable inhibitor of human immunodeficiency virus type 1 protease with potent antiviral activity. 825 28

Via a combination of chemical and enzymatic synthesis, new hexapeptide substrates convenient for use in activity assessment of several aspartyl proteinases--porcine pepsin, human pepsin, gastricsin, and cathepsin D--were prepared. These peptide derivatives, o-aminobenzoyl-Ala-Ala-Phe-Phe-Ala-Ala-p-nitroanilide and N-(o-aminobenzoyl-Ala-Ala-Phe-Phe-Ala-Ala)-N'-2,4-dinitrophenyl ethylenediamine, contain a fluorescent o-aminobenzoyl moiety as well as p-nitroaniline or N-2,4-dinitrophenyl ethylenediamine--the groups that cause fluorescence quenching. Aspartyl proteinases hydrolyze the Phe-Phe peptide bond in the substrates, which diminishes quenching due to separation of the fluorescent and quenching moieties and leads to an increase in the fluorescence intensity of o-aminobenzoyl residue. Abz-Ala-Ala-Phe-Phe-Ala-Ala-Ded, being fairly well hydrolyzed by HIV proteinase, might be used for assay of this enzyme.
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PMID:Fluorogenic peptide substrates for assay of aspartyl proteinases. 871 88

Various analogs of statine, a remarkable amino acid component of the protease inhibitor pepstatine, were synthesized and evaluated as tripeptide derivatives for their activity against cathepsin D and HIV-1 protease.
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PMID:Inhibition of cathepsin D by tripeptides containing statine analogs. 1042 75

Blood flukes of the genus Schistosoma currently infect millions of people in tropical and subtropical countries. An enzyme playing a major role in hemoglobin (Hb) degradation by Schistosoma mansoni has been cloned and shown to be highly similar to the human cathepsin D aspartyl proteinase, although presenting a distinct substrate specificity from the latter. Investigating the structural features responsible for this difference has a major application in the design of selective anti-schistosomal drugs. In order to achieve this goal a homology model for the S. mansoni aspartyl hemoglobinase was constructed and then used to simulate the complexes formed with two transition state analogues of Hb-derived octapeptide substrates. Comparison with human cathepsin D showed that different pocket volumes and surface electrostatic potentials arise from substitutions in residues comprising the S4, S3, S2 and S3' subsites. Since the primary specificity of the S. mansoni enzyme resembles that of HIV-1 protease, we have discussed the applicability of current retroviral protease inhibitors as leads for the design of new anti-schistosomal drugs.
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PMID:Exploring the subsite specificity of Schistosoma mansoni aspartyl hemoglobinase through comparative molecular modelling. 1194 40

The aspartic proteinases are a family of enzymes involved in a number of important biological processes. In animals the enzyme renin has a hypertensive action through its role in the renin-angiotensin system. The retroviral aspartic proteinases, such as the HIV proteinase, are essential for maturation of the virus particle and inhibitors have a proven therapeutic record in the treatment of AIDS. The lysosomal aspartic proteinase cathepsin D has been implicated in tumorigenesis and the stomach enzyme pepsin, which plays a major physiological role in hydrolysis of acid-denatured proteins, is responsible for much of the tissue damage in peptic ulcer disease. Since aspartic proteinases also play major roles in amyloid disease, malaria and common fungal infections such as candidiasis, inhibitors to these enzymes are much sought after as potential therapeutic agents. In all aspartic proteinases, the catalytic aspartate residues are involved in an intricate arrangement of hydrogen bonds involving a solvent molecule which is presumed to be water. The catalytic mechanism is thought to involve nucleophilic attack of the active site water molecule on the scissile bond carbonyl generating a tetrahedral gem-diol intermediate. The design of inhibitors generally involves the use of short oligopeptides containing a transition state analogue which mimic this tetrahedral intermediate. The application of structure-based drug design to members of the aspartic proteinase family is the main subject of this review.
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PMID:Aspartic proteinases in disease: a structural perspective. 1195 98

Aza-peptide epoxides, a novel class of irreversible protease inhibitors, are specific for the clan CD cysteine proteases. Aza-peptide epoxides with an aza-Asp residue at P1 are excellent irreversible inhibitors of caspases-1, -3, -6, and -8 with second-order inhibition rates up to 1 910 000 M(-1) s(-1). In general, the order of reactivity of aza-peptide epoxides is S,S > R,R > trans > cis. Interestingly, some of the R,R epoxides while being less potent are actually more selective than the S,S epoxides. Our aza-peptide epoxides designed for caspases are stable, potent, and specific inhibitors, as they show little to no inhibition of other proteases such as the aspartyl proteases porcine pepsin, human cathepsin D, plasmepsin 2 from P. falciparum, HIV-1 protease, and the secreted aspartic proteinase 2 (SAP-2) from Candida albicans; the serine proteases granzyme B and alpha-chymotrypsin; and the cysteine proteases cathepsin B and papain (clan CA), and legumain (clan CD).
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PMID:Design, synthesis, and evaluation of aza-peptide epoxides as selective and potent inhibitors of caspases-1, -3, -6, and -8. 1499 41


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