Background and purpose: Nitric oxide (NO) is produced by nitric oxide synthase (NOS) from L-arginine and has an important role in a variety of physiological and pathological processes in biological systems. In this study, KINETIC activities of isolated NOS were evaluated from sheep kidney.Materials and methods: In this research homogenization, ammonium sulfate precipitation and column chromatography on DEAE-32 Cellulose and 2', 5' -ADP-agarose of 500 grams of sheep kidney were used to purify isolated nitric oxide. In all steps of purification process the amount of protein and its activity was assayed using Bradford and Griess reactions.Results: The molecular weight of sheep kidney on SDS-PAGE electrophoresis was 54 KD.Specific activity was 0.6 units/mg protein and recovery of purification was 0.9% (relative purity was 20 times more). Optimum temperature and pH were 30oC and 7.4 and incubation of purified ENZYME at thermal interval of 10 to 30oC for 15 minute showed a stable ENZYME activity. At 75mM concentration of L-arginine substrate, the highest level of NOS activity was seen. The Vmax and Km of ENZYME were 250 nmol/min/mg protein and 5.32mM, respectively.Conclusion: NOS ENZYME from sheep kidney was purified with relative purity of 20 times and their optimum temperature, pH, suitable substrate concentration, Vmax and Km were 30oC, 7.4, 75mM, 250 nmol/min/mg proteins and 5.32mmol, respectively.

Background: The aim of this study isthe investigation of type of buffer (as an environmental factor) on xanthan lyase activity, a xanthan-degrading ENZYME from Paeni Bacillus SP.SM0.Methods: In the present study, bacterial xanthan lyase was cultured in fluid culture media. Supernatant was collected and activity of the ENZYME was measured. Xanthan lyase activity was monitored by measuring the increase of A235 caused by conjugation of the formed C=C bond with the carboxylate group in the uronic acid residue.Results: The ENZYME saturation curve (Michaelis-Menten plot) was plotted in increasing concentrations of xanthan (substrate) in the presence of both phosphate and tris-HCl buffer. Vmax and Km of the ENZYME were measured and comprised.Conclusion: According to the parameters, it can be deduced that buffer has an effect on xanthan lyse activity and tris-HCl buffer is more suitable for a better activity of xanthan lyase.

Attempts to obtain experimental values for the KINETIC parameters of phenanthridine oxidation by guinea pig or rabbit liver aldehyde oxidase using common spectrophotometric methods have not been successful due to a lower limit of detection. In the present study, a new spectrofluorimetric assay in combination with a multivariate calibration method for enzymatic KINETIC study of aldehyde oxidase activity, using phenanthridine as the substrate, has been developed and validated. Phenanthridine and phenanthridinone binary mixtures were prepared in a dynamic linear range of 0.025-1 mM and the emission flourimetric spectra of the solutions recorded at the excitation and emission wavelengths of 236 and 320-450 nm, respectively. The optimized calibration model of partial least squares (PLS) method was applied for the simultaneous determination of the concentration of each chemical in the prediction set. The limits of detection for phenanthridine and phenanthridinone were found to be 2.13 ± 0.33 and 3.41 ± 0.34 nM (mean ±  SD, n = 5), respectively. This method was then used for KINETIC study of phenanthridine oxidation using guinea pig and rat hepatic aldehyde oxidase. The results were compared with those obtained from a univariate spectroscopic method. Using this new spectrofluorimetric-multivariate calibration method, the Km value for the oxidation of phenanthridine with guinea pig and rat liver aldehyde oxidase were obtained as 0.83 ±  0.08 and 2.20 ±  0.40, mM (mean ±  SD, n = 3), respectively.

In this work, Picard iteration method is used to obtain analytical expressions for the prediction of molar concentration of native and denatured jack bean urease (EC 3. 5. 1. 5) through the three-reaction steps KINETIC model of thermal inactivation of the urease. The obtained solutions are used to study the KINETICs of thermal inactivation of the ENZYME as applied in biotechnology. The analytical solutions are verified with numerical solutions using Runge – Kutta with shooting method and good agreements are established between the solutions. From the parametric studies using the iterative method, the molar concentration of native ENZYME decreases as the time increases while the molar concentration of the denatured ENZYME increases as the time increases. The time taken to reach the maximum value of the molar concentration of native ENZYME is the same as the time taken to reach the minimum value of the molar concentration of the denature ENZYME. The information given in this theoretical investigation will assist in the KINETIC analysis of the experimental results over handling rate constants and molar concentrations.

Aims Proteinase K is an extracellular endopeptidase, which is secreted by Tritirachium album Limber and belongs to the serine endopeptidase class. This ENZYME is extensively applied to protein-related studies. The present study aimed at evaluating the effect of urea, guanidine hydrochloride (GnHCl), and organic solvents on the KINETIC activity of proteinase K ENZYME. Materials & Methods In this experimental study, KINETICs studies were performed, using UVVis spectrophotometer on different concentrations of substrate, urea, and GnHCl at 40˚ C and pH 7. 4. Findings Urea decreased the Vmax and Km of ENZYME at 1 and 2molar concentrations, but at higher concentrations such as 3 and 4molar, it increased ENZYME activity. GnHCl had an inhibitory effect on the ENZYME activity, resulting in a decrease in Vmax and Km in 1, 2, and 3molar concentrations and acted as an uncompetitive inhibitor. Organic solvents including methanol, ethanol, and isopropanol had activatory effect at low concentrations and inhibitory effect at high concentrations on the KINETIC activity of proteinase K ENZYME. Conclusion Urea has an inhibitory effect at low concentrations and an activatory effect on the activity of the ENZYME at a concentrations above 2molar, but GnHCl has an inhibitory effect at all concentrations and can be used as an ENZYME inhibitor. The effect of organic solvents including methanol, ethanol, and isopropanol on the activity of the proteinase K ENZYME depends on their volume/volume percent; they cause ENZYME activation at low percentages, but have inhibitory effect at high percentages, so that activates methanol below 30% and isopropanol below 50%.

Background and Objectives: Creatine kinase catalyzes the reversible transfer of a phosphoryl group from ATP to creatine, producing phosphocreatine (phosphagen). Phospho creatine as an energy source has an important role for sperm motility. Therefore, proper function of creatine kinase is the main factor of energy preparation for sperm movement. The aim of this study was to study the optimum in vitro creatine kinase ENZYME KINETIC after its isolation from human sperm.Subjects and Methods: Creatine kinase was extracted from approximately 30 ml human semen related to 10 health men with age average 30±5 years, after washing, centrifuge and chromatography of sperms on DEAE-32 column. In each step of purification, protein levels and ENZYME activity were assayed according to Bradford and Rosalki methods, respectively.Results: Results this study showed that human sperm creatinine kinase activity increased by 67% with increase of the creatine phosphate concentration from 0.5 to 10 mM. Moreover pH change from 6 to 6.8 also showed an increase in the activity of this ENZYME. Ceatine kinase activity increased in the temperature range of 20 to 40oC.Conclusion: Our results showed that the most suitable substrate concentration, temperature and pH for optimum activity of human sperm creatine kinase were at 3 mM, 40oC and 6.8 respectively.

Background: A high level of replication is one of the main indicators of tumors. Tumor cells have to manufacture and transport macromolecules into daughter cells. One of the required ENZYMEs is malic ENZYME, which generates the NADPH for fatty acid synthesis in order to make cell membrane and pyruvate, and support the glycolysis pathway to supply the energy demand. Due to the enormous proliferation of cancer cells, it is likely that the activity of malic ENZYME in cancer cells is more than normal cells. The aim of this study is to survey the KINETICs of malic ENZYME in tumor and normal breast tissues. Methods: We obtained the tumor and normal breast tissue specimens directly from the operating room. The assays were performed with partially purified samples under optimum conditions for the substrate and co-factor requirements. The velocity of the ENZYME or Michaelis-Menten constant, maximum velocity, and the amount of inhibitor that reduced the ENZYME activity by 50% were obtained and calculated in all samples. Results: The Michaelis-Menten constant for malate was lower in tumors compared to normal samples. In contrast, the maximum velocity for malate in tumors was higher than normal tissues, whereas the amount of inhibitor that reduced the ENZYME activity by 50% of guanidine hydrochloride and sodium chloride were both higher in tumors than normal tissues. Conclusion: The obtained results indicated that the malic ENZYME KINETICs had different patterns in tumor tissues in comparison with normal tissues. A higher affinity of malic ENZYME for pyruvate production in tumors supported high aerobic glycolysis. Moreover, it could be an approach to connect glutaminolysis to the glycolysis pathway. Malic ENZYME could be a target to inhibit the glycolysis and glutaminolysis pathways in tumors.

In this study, the some KINETIC and biochemical properties of trypsin ENZYME from common kilka and porcine were assessed. The results showed that the optimum temperature and pH for common kilka trypsin and porcine trypsin were 60oC and 8, respectively. Thermal and pH stability were also 45°C and 7-10 for common kilka trypsin and 50oC and 4-11 for porcine trypsin. CaCI2 and MgCI2 significantly increased the trypsin activity in common kilka and porcine (P<0.05). NaCI and KCI had no significant effect on trysin activity in common kilka (P>0.05) while it was significantly decreased in porcine in presence of them (P<0.05). The trypsin activity in common kilka was significantly increased in presence of MnCI2 (P<0.05) but in porcine, showed a significant decrease (P<0.05). The comparison of inhibitors of SBTI, TLCK, PMSF and p-aminobenzamidine revealed the except for p-aminobenzamidine, the other inhibitors showed no significant difference on ENZYME activity in common kilka and porcine (P>0.05) but ENZYME activity was significantly decreased by p-aminobenzamidine in porcine than common kilka (P<0.05). Vmax value of common kilka trypsin was significantly higher max than that from porcine trypsin (P<0.05). Km value of common kilka trypsin was significantly lower than that from porcine trypsin (P<0.05). The results of this study showed that common kilka trypsin was more efficient that porcine.trypsin and it could be considered as an additive in industries and biotechnological researches in future.

Background: Dry cough is the most common adverse effect and limiting factor of all angiotensin converting-ENZYME inhibitors (ACEIs). Prostaglandins have been pinpointed as playing an important role in the genesis of this problem. This double blind clinical trial desinged to study the efficacy of 500 milligram (mg) of aspirin comparing with placebo in controlling Enalapril-induced cough. Methods: The subjects were 32 patients who had developed Enalapril-induced cough. They were randomized into two groups: a group of daily dose of aspirin, 500 mg and a group of placebo for a treatment period of 4 weeks. Mean of cough severity was compared between two groups before treatment and weekly, until 4 weeks. Results: Mean of cough severity in aspirin and placebo groups before and at the end of first week of treatment did not show any significant difference. After the second, third, and fourth weeks, cough severity scores were significantly reduced in aspirin group (p<0.001). Conclusion: 500mg aspirin, once daily, can suppress or abolish Enalapril-induced cough and this finding proposes alternative therapeutic approach for ACEIs-induced related cough.