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1

Kinetics properties of polyphenol oxidase in hawthorn (Crataegus spp.)

100%

Saeidian S.

International Letters of Natural Sciences

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2014

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tom 20

EN

Polyphenol oxidase (PPO) from hawthorn was extracted and partially purified through (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in Crataegus spp. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the substrates tested, catechol was the best substrate for PPO with a Km value of 2.2 mM. The optimum pH for PPO activity was found to be 7. The enzyme showed high activity over a broad pH range of 4 - 8. The optimal pH and temperature for enzyme activity were found to be 7 and 40-45 °C, respectively. km value for hawthorn PPO is calculated 22 mM for catechol and 6.7 mM for pyrogallol and 9.7 mM for L-dopa. As can be seen, affinity of PPOs for various substrates varies widely. The enzyme showed a broad activity over a broad pH and temperature range. The thermal inactivation studies showed that the enzyme is heat resistant. The enzyme showed the highest activity toward pyrogallol and no activity toward tyrosine. Of the inhibitors tested, the most potent inhibitors were kojic acid, cysteine and glycine , respectively.

2

Inhibition of Diphenol Oxidase Activity of Strawberry (Fragaria Sp) Using L-Cysteine and L-Glycine

100%

Saeidian S.

International Letters of Chemistry, Physics and Astronomy

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2015

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tom Vol. 48

194--202

EN

L-glycine and L-cysteine exhibit, strong inhibition of partial purified DIPHENOL OXIDASE at strawberry. The concentration of L-glycine inhibiting Diphenol oxidase activity by 50% (IC50) was 0.5 and 0.4 mM at pH 6.7 and 8, respectively. The inhibition of partial purified Diphenol oxidase activity is pH and inhibitor dependent. Kinetic studies indicate that L-glycine is a uncompetetive inhibitor and L-cysteine is competitive and noncompetitive inhibitor of Diphenol oxidase activity. Vmax and Km for catechol oxidation at pH 6.7 and in presence of L-glycine (1.4M) was 0.09 ∆A min-1 and 10 mM. Vmax for catechol oxidation at pH 8 and in absence of L-glycine was 0.09 ∆A min–1, with a Km of 3.5 mM. Kinetics parameters indicated the highest catalytic efficiency ( units mg–1 prot mM–1) with catechol and L-glycine at pH 8: 4 , then with L-cystein at pH 8: 1.7, L-glycine at pH 6.7: 1.4 and L-cystein at pH 6.7: 0.25.

3

Inhibition of diphenol oxidase activity of strawberry (Fragaria sp) using L-cysteine and L-glycine

100%

Saeidian S.

International Letters of Natural Sciences

|

2015

|

tom 40

4

Effect of temperature on guaiacol peroxidase of Pyrus communis

63%

Saeidian S. , Ghasemifar E.

International Letters of Natural Sciences

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2013

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tom 05

EN

Peroxidase (EC 1.11.1.7; donor: hydrogen-peroxide oxidoreductase, POD) is one of the key enzymes controlling plant growth, differentiation and development. The enzyme participates in construction, rigidification and eventual lignification of cell walls, biosynthesis of ethylene from 1-aminocyclopropane-1-carboxylic acid and H2O2, regulation of auxin level through auxin catabolism, protection of tissue from damage and infection by pathogenic microorganisms, the oxidation of indoleacetic acid. For peroxidase activity in wild pears extract one pH optimum was observed at 6.5 that probably belong to atleast one isoenzyme. Activity of peroxidase in presence of guaiacol and H2O2 was optimum after incubation at 40 °C. Maximum activity of peroxidase is 300 % .Activity increased to 240 %, 300 %, 70 % and 10 % after 60 minute incubation at 30, 40, 45 and 60 °C for peroxidase. Incubation at high temperature (70 °C) was accompanied with decrease of activity to 10 % peroxidase activity.

5

Effects of anaerobic exercise in the morning and evening sessions on some coagulation factors in non-athletes female students of Islamic Azad University of Sanandaj

51%

Tabatabai E. F. , Hematfar A. , Saeidian S.

International Letters of Natural Sciences

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2014

|

tom 05

EN

The purpose of the present research is compare the effects of coagulation factors in non-athletes gilrs after exhaustive anaerobic activity sessions in the morning and evening. Present study was semi-emprical that was done on 12 non-athlete female students in range of 18-24 years. Exercise protocol was RAST test, that in which each person passed amain 35 meters of distance for 6 times and rest 10 seconds between each stage. Blood sampling was performed Once in the morning (8 am) and a later week in evening (5 pm) in two stages (before and after). Datas were analyzed with Kolmogorov Smirnov test, Levine's test and two-way ANOVA level (p < 0/05 ). The results showed that there was not significative difference between the effects of an anaerobic activity in the morning and in the evening on hematocrit, platelet, partial time Thromboplastin (PTT), Prothrombin time (PT) and fibrinogen in non-athletic subjects. Findings showed that training for normal persons, non-athletes and patients, especially patients with clotting problems, and cardiovascular disease will be suggeste, each activity to be act with caution at morning and during the day.