scholarly journals Determination of aspartate kinase activity in maize tissues

2005 ◽  
Vol 62 (2) ◽  
pp. 184-189 ◽  
Author(s):  
Renato Rodrigues Ferreira ◽  
Ariane Vendemiatti ◽  
Priscila Lupino Gratão ◽  
Peter John Lea ◽  
Ricardo Antunes Azevedo
Keyword(s):  
Enzyme Activity ◽  
Kinase Activity ◽  
Higher Plants ◽  
Aspartate Kinase ◽  
Optimum Temperature ◽  
Callus Cell ◽  
Maize Plants ◽  
Aspartate Pathway ◽  
And Storage

Lysine, threonine, methionine and isoleucine are synthesized from aspartate in a branched pathway in higher plants. Aspartate kinase plays a key role in the control of the aspartate pathway. The enzyme is very sensitive to manipulation and storage and the hydroxamate assay normally used to determine aspartate kinase activity has to be altered according to the plant species and tissue to be analyzed. We have optimized the assay for the determination of aspartate kinase in maize plants callus cell cultures. Among all the assay parameters tested, the concentration of ATP/Mg and temperature were critical for enzyme activity. In the case of temperature, 35°C was shown to be the optimum temperature for aspartate kinase activity.

scholarly journals FLUORIMETRIC DETERMINATION OF CREATINE KINASE ACTIVITY IN ISOLATED SINGLE NEURONS

1973 ◽  
Vol 21 (6) ◽  
pp. 568-571 ◽  
Author(s):  
IGOR B. KRASNOV
Keyword(s):  
Creatine Kinase ◽  
Enzyme Activity ◽  
Coefficient Of Variation ◽  
Kinase Activity ◽  
Tissue Sample ◽  
Vestibular Nucleus ◽  
Creatine Kinase Activity ◽  
Single Neurons ◽  
Fluorimetric Determination

A quantitative fluorimetric method for determination of creatine kinase activity in isolated single nerve cells (2-10 ng dry weight) has been developed. Enzyme activity was measured in the direction of adenosine triphosphate and creatine formation. The creatine generated was measured by the fluorescent compound formed with ninhydrin in alkali. The coefficient of variation for the assay of enzyme activity in brain homogenate (47 ng wet tissue/sample) was 3.17%. The coefficient of variation for single neurons of the lateral vestibular nucleus (nucleus Deitersi) in rabbit was about 15%. The creatine kinase activity in these cell bodies was 342.0 ± 14.2 moles/kg dry tissue/hr, at 38°C.

scholarly journals Isolation of enzymes involved in threonine biosynthesis from sorghum seeds

2004 ◽  
Vol 16 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Renato Rodrigues Ferreira ◽  
Ariane Vendemiatti ◽  
Lyndel Wayne Meinhardt ◽  
Peter John Lea ◽  
Ricardo Antunes Azevedo
Keyword(s):  
Amino Acids ◽  
Essential Amino Acids ◽  
Aspartate Kinase ◽  
Homoserine Dehydrogenase ◽  
Higher Plant ◽  
Level Of Activity ◽  
Immature Seeds ◽  
Aspartate Pathway ◽  
Threonine Biosynthesis

Cereal seeds are poor in essential amino acids, particularly lysine, tryptophan and threonine. The amino acids lysine and threonine are synthesized in the aspartate pathway. Although most of the enzymes of the aspartate pathway have been isolated and characterized in higher plant species, the metabolism of lysine and threonine is totally unknown in sorghum. We have isolated two enzymes, aspartate kinase (AK) and homoserine dehydrogenase (HSDH) from sorghum. Optimum assay conditions were established for the determination of AK and HSDH activities. The highest level of activity was observed in immature seeds. AK was shown to be inhibited by threonine and lysine indicating the existence of at least two isoenzymes, one sensitive to threonine inhibition and the other sensitive to lysine inhibition with the latter being predominant in sorghum seeds. HSDH was shown to be inhibited by threonine indicating the existence of a threonine-sensitive HSDH, however, most of the activity was not inhibited by threonine, suggesting the existence of a second predominant isoenzyme of HSDH resistant to threonine inhibition.

Effects of Ca, Mg, and EDTA on creatine kinase activity in cerebrospinal fluid.

1979 ◽  
Vol 25 (1) ◽  
pp. 147-150 ◽  
Author(s):  
P Urdal ◽  
J H Strømme
Keyword(s):  
Cerebrospinal Fluid ◽  
Creatine Kinase ◽  
Enzyme Activity ◽  
Kinase Activity ◽  
Creatine Kinase Activity ◽  
Precise Estimate ◽  
The Relationship ◽  
Sample Fraction ◽  
Sensitive Method

Abstract For one to obtain a precise estimate of creatine kinase (CK) activity in cerebrospinal fluid, the sample fraction is increased by about 10-fold over that used for serum. This increases the concentration of interfering substances, Ca being especially important. Therefore, the relationship between Ca, Mg, and EDTA was examined. Enzyme activity was maximal with 15 mmol of Mg per liter in the presence of 3 mmol of EDTA per liter, otherwise according to the (Scandinavian) recommended conditions for determination of CK activity in serum. These modifications increased the activity of CK by 35% for CK-MM and by 60% for CK-BB. Counteraction of Ca-induced inhibition was the main reason to this increase. We describe a practical and sensitive method for determining CK in cerebrospinal fluid.

scholarly journals Effect of Methyl Jasmonate, Cytokinin, and Lavender Oil on Antioxidant Enzyme System of Apricot Fruit (Prunus armeniaca L.)

2021 ◽  
Vol 13 (15) ◽  
pp. 8565
Author(s):  
Seyda Cavusoglu ◽  
Nurettin Yilmaz ◽  
Firat Islek ◽  
Onur Tekin ◽  
Halil Ibrahim Sagbas ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Methyl Jasmonate ◽  
Prunus Armeniaca ◽  
Lavender Oil ◽  
Defense Systems ◽  
Antioxidant Enzyme System ◽  
Prunus Armeniaca L ◽  
Antioxidant Defense Systems ◽  
And Storage

Various treatments are carried out in order to extend both the shelf life and storage life of fresh fruit and vegetables after harvest and among them non-toxic for humans, environmentally and economically friendly alternative treatments are gained more importance. In the current study, methyl jasmonate (MeJA), cytokinin, and lavender oil which are eco-friendly and safe for human health were applied on apricot fruit. The treated fruit were stored at 0 °C and 90–95% relative humidity for 25 days and catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) enzyme activities and lipid peroxidation of apricots after treatments were studied. According to the findings obtained from the study, it was observed that 5 ppm cytokinin and 1000 ppm lavender oil treatments of apricot fruit gave better APX and CAT enzyme activity, respectively. In addition, better SOD enzyme activity in fruit was obtained with MeJA+lavender oil treatments. As a result, it can be emphasized that the product quality of apricot fruit is preserved as both the eco-friendly application of MeJA, cytokinin, and lavender oil separately from each other and the treatment of combinations between these compounds activate the enzymatic antioxidant defense systems of apricot fruit after harvest.

A Rapid Electrophoretic Method for the Determination of the Isoenzymes of Serum Lactate Dehydrogenase

1966 ◽  
Vol 12 (5) ◽  
pp. 308-313 ◽  
Author(s):  
Albert W Opher ◽  
Charles S Collier ◽  
Joseph M Miller
Keyword(s):  
Enzyme Activity ◽  
Lactate Dehydrogenase ◽  
Quantitative Determination ◽  
Serum Lactate ◽  
Serum Lactate Dehydrogenase ◽  
Electrophoretic Method ◽  
The Individual ◽  
Electrophoretic Procedure ◽  
Purple Formazan

Abstract A convenient electrophoretic procedure for the separation and quantitation of lactate dehydrogenase (LDH) isoenzymes is described. The system uses polyacetate Sepraphore III strips.* The areas of activity are shown by incubation with an LDH substrate combined with tetra-nitro-blue-tetrazolium. The reduction of the latter to the purple formazan is quantitatively related to the enzyme activity. Quantitative determination of the individual colored areas is performed by densitometry.

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