[Effect of cyanopyrrolidine derivatives on the activity of prolylendopeptidase, acute exudative inflammation and visceral pain in mice]. / Vliianie proizvodnykh tsianopirrolidina na aktivnost' proliléndopeptidazy, ostroe ékssudativnoe vospalenie i vistseral'nuiu bol' u myshei.

Cyanopyrrolidine derivatives benzyloxycarbonyl-methionyl-cyanopyrrolidine (ZMetPrdN), benzyloxycarbonylphenylalanyl- cyanopyrrolidine (ZPhePrdN), tert-butyl-hydroxycarbonyl-glycyl-cyanopyrrolidine (BocGlyPrdN), tert-butyl-hydroxycarbonyl-methionyl-cyanopyrrolidine (BocMetPrdN) are inhibitors of prolylendopeptidase (PREP; EC 3.4.21.26) with an IC50 of 2 nM to 12 nM. ZMetPrdN, ZPhePrdN and BocMetPrdN additionally inhibited dipeptidyl peptidase IV (DPP-4; EC 3.4.14.5) with an IC50 of 1100 nM to 3200 nM. All the compounds have antinociceptive properties in the acetic acid writhing test in mice. But only cyanopyrrolidine derivatives with aromatic substituents decrease exudative inflammation. The cyanopyrrolidine derivatives also increase PREP activity and compensatorily reduce DPP-4 activity in the serum of mice three hours after the induction of inflammation. Thus, cyanopyrrolidine derivatives exhibit antinociceptive and antiexudative properties in part via their effect on PREP.

[Effect of afobazole and levodopa on the activity of proline-specific proteinases and adenosine deaminase in blood serum and brain structures of rats with experimental Parkinson's syndrome induced by systemic administration of rotenone]. / Vliianie afobazola i levodopy na aktivnost' prolinspetsificheskikh proteinaz i adenozindezaminazy v syvorotke krovi i strukturakh golovnogo mozga krys s éksperimental'nym parkinsonicheskim sindromom, vyzvannym sistemnym vvedeniem rotenona.

Rats with experimental Parkinson's syndrome induced by seven-day intraperitoneal administration of rotenone at a dose of 2.75 mg/kg have an increased activity of prolylendopeptidase (EC 3.4.21.26, PREP) in blood serum and a decreased activity of adenosine deaminase (EC 3.5.4.4, ADA) in serum and in the prefrontal cortex. PREP and ADA activity in other brain structures (in the striatum, hypothalamus and hippocampus) did not change; dipeptidyl peptidase IV activity (EC 3.4.14.5, DPP-4, CD26) also remained constant in serum and in all the brain structures investigated. Afobazole and levodopa, which exhibit antiparkinsonian activity in this model of Parkinson's syndrome, decrease elevated PREP activity in serum and increase reduced ADA activity in the prefrontal cortex of rats with the experimental pathology. Meanwhile, treatment with the study drugs was associated with a decrease of ADA activity in the other brain structures.

Activities of Proline-Specific Proteinases in the Serum and Cerebrospinal Fluid of Rats with the Fetal Valproate Syndrome.

In 60-day-old Wistar rats with fetal valproate syndrome, the brain to body weight ratio was higher by 9.4% and activity of dipeptidyl peptidase IV in the serum and cerebrospinal fluid was higher by 18.4 and 40.6%, respectively, than in healthy controls. Activity of prolylendopeptidase in the serum and cerebrospinal fluid in rats with the fetal valproate syndrome did not differ from the control.

[Protective effect of endothelin-1 in goldblatt "one-kidney, one-clip" hypertension].

The aim of the study was to evaluate the effect of chronic inhibition of endothelin-1 (ET-1) synthesis on renovascular hypertension development. Male Wistar rats were subjected to an operation, according to the "1 kidney, 1 clip" method and were given an endothelin-converting enzyme inhibitor PP36 per os with drinking water for 4 weeks. Serum urea rose by 21% in hypertensive rats and by 44% in PP36 treated hypertensive rats. PP36 treatment resulted in blood pressure rise both in the Sham group (compared to the initial blood pressure level) and in hypertensive rats (compared to hypertensive control group). Significant reduction of circulating ET-1 after chronic PP36 administration by 28% was obtained only in normotensive, but not hypertensive rats. Circulating ET-1 was not altered in hypertensive rats, but ET-1 excretion rate was significantly enhanced by 90%, which was abolished by PP36. We suggest that chronic reduction of ET-1 synthesis in the kidney might lead to water and salt retention.

[Fluorescence-based determination of enzyme activity of recombinant CYPS1B1 (sterol 14alpha-demethylase) with coumarin derivatives].

The current investigation was undertaken with the aim to carry out an in vitro evaluation of the ability of coumarin derivatives as probe substrates to predict the activity of CYP51b1. The results obtained indicate that 7-aminocoumarin-4-acetic acid (ACAC) can be used to determine the recombinant CYP51b1 activity. Determination of CYP51b1 activity with ACAC is based on the direct registration of fluorescence increasing at 30 degrees C. It was found also that BMR in a simple soluble model system can be used as an electron donor for CYP51B1. Fluorescence-based assay is highly sensitive and can be used for the screening of sterol 14alpha-demethylase inhibitors.

[Study of substrate specificity of a new peptide substrate of endothelin converting enzyme].

The new fluorogenic hexapeptide substrate CMC-Ala-Gly-Gly-Trp-Phe-Arg was used as substrate for endothelin-converting enzyme (ECE), angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The specific inhibitors lisinopril (ACE) and thiorphan (NEP) were used for identification of these enzyme activities,

Optical biosensor investigation of interactions of biomembrane and water-soluble cytochromes P450 and their redox partners with covalently immobilized phosphatidylethanolamine layers.

A phospholipid-containing biochip was created by covalently immobilizing phospholipids on the optical biosensor's aminosilane cuvette and employed to monitor the interactions of the membrane and water-soluble proteins in cytochrome P450-containing monooxygenase systems with planary layers of dilauroylphosphatidylethanolamine (DLPE) and distearoylphosphatidylethanolamine (DSPE), differing in acyl chain length. It was shown that the full-length membrane proteins-cytochrome P4502B4 (d-2B4), cytochrome b5 (d-b5) and NADPH-cytochrome P450 reductase (d-Fp)-readily incorporated into the phospholipids. The incorporation was largely due to hydrophobic interactions of membranous protein fragments with the phospholipid layer. However, electrostatic forces were also but not always involved in the incorporation process. They promoted d-Fp incorporation but had no effect on d-b5 incorporation. In low ionic strength buffer, no incorporation of these two proteins into the DSPE lipid layer was observable. Incorporation of d-b5 into the DLPE layer was abruptly increased at temperatures exceeding phospholipid phase transition point. Incorporation of d-2B4 was dependent on its aggregation state and decreased with increasing protein aggregability. Water-soluble proteins either would not interact with the phospholipid layer (adrenodoxin) or would bind to the layer at the cost of only electrostatic (albumin) or both electrostatic and hydrophobic (P450cam) interactions.

Characterization of bovine atrial angiotensin-converting enzyme.

Bovine atrial angiotensin-converting enzyme (ACE) was purified to electrophoretic homogeneity. The purification procedure included ion-exchange chromatography on DEAE-Toyopearl 650M, affinity chromatography on lisinopril-agarose and gel filtration on Sephadex G-100. The bovine atrial ACE exhibited similar sensitivities to inhibition by lisinopril and captopril as lung ACE (the Ki values for the atrial and lung enzymes differed insignificantly). However, the kinetic parameters of hydrolysis of some synthetic tripeptide substrates (FA-Phe-Gly-Gly, FA-Phe-Phe-Arg, Cbz-Phe-His-Leu, Hip-His-Leu) catalyzed by bovine atrial and lung ACE varied to a greater extent. The enzymes were also characterized by some differences in activation by chloride, nitrate, and sulfate anions. These data support the hypothesis of tissue specificity of ACEs.

[Correction of cardiac functions in rats with experimental myocardial ischemia by chronic administration of endothelin-converting enzyme inhibitor]. / Korrektsiia funktsional'nogo sostoianiia serdtsa krys s éksperimental'noi ishemiei miokada pri khronicheskom primenenii ingibitora éndotelin-prevrashchaiushchego fermenta.

Experiments on chronically instrumented Wistar rats demonstrated that 15 mm microsphere embolization of coronary arteries led to a significant decrease in the systemic (APsyst) and maximal left ventricular systolic pressures (LVSPmax) to 10.1 and 21.1%, respectively (p < 0.05). To evaluate the role of endothelin in this pathology, the inhibitor of endothelin-converting enzyme (ECE), PP-36, was used. PP-36 abolished hemodynamic changes caused by embolization after 4 days per os treatment (starting 2 days before surgical procedure). Dobutamine test revealed marked decrease of LVSPmax and +dP/dtmax responses in the embolized versus sham operated animals. PP-36 normalized ischemical heart response to beta-adrenergic stimulation. Maximal APsyst and LVSPmax increases were observed in embolized rats. PP-36 abolished this effect and led to parallel rising reaction to aminoguanidin in embolized (APsyst: +12.4 +/- 1.6 vs. +6.8 +/- 2.3 mmHg, p < 0.05) as well as in sham operated rats (APsyst: +8.5 +/- 1.1 vs. +5.6 +/- 0.7 mmHg, p < 0.05). Thus, the present research showed the possibility to correct ischemical heart disturbance by using a new ECE inhibitor, PP-36. One possible mechanism of this drugs action may include systemic or myocardial changes in NO contribution to the maintenance of normal arterial pressure.

Monoamine oxidase inhibition by N-alkyloxycarbonyl derivatives of ethylene diamine.

Urethane type derivatives of ethylene diamine (EDA) were synthesized and tested as inhibitors of rat liver mitochondrial monoamine oxidase (MAO) A and B. The nature of the aromatic ring and the position of substituents in it were crucial for manifestation of the inhibitory activity. 3,4- and 2,4-Chlorobenzyloxycarbonyl-EDA derivatives were the most potent MAO A inhibitors. The inhibition of both MAO A and to a lesser extent MAO B depended on preincubation time with these inhibitors. The activity of both enzymes did not recover completely after repeated sedimentation and resuspension of inhibitor-treated mitochondria. The data suggest that these compounds exhibit properties of tight-binding reversible inhibitors of MAO A and B. The development of a new generation of MAO inhibitors causing simultaneous reversible nonselective inhibition of MAO A and B must meet one important criterion, the same type of inhibition of both the enzymes.