scholarly journals The control of CTP:choline-phosphate cytidylyltransferase activity in pea (Pisum sativum L.)

1986 ◽  
Vol 240 (3) ◽  
pp. 837-842 ◽  
Author(s):  
M J Price-Jones ◽  
J L Harwood
Keyword(s):  
Enzyme Activity ◽  
Pisum Sativum ◽  
Subcellular Distribution ◽  
Microsomal Fraction ◽  
Control Mechanisms ◽  
Stem Tissue ◽  
Enzyme Protein ◽  
Pisum Sativum L ◽  
Ylacetic Acid ◽  
Stimulation Of

Several possible control mechanisms for CTP:choline-phosphate cytidylyltransferase (EC 2.7.7.15) activity in pea (Pisum sativum L.) stems were investigated. Indol-3-ylacetic acid (IAA) treatment of the pea stems decreased total cytidylyltransferase activity but did not affect its subcellular distribution. Oleate (2 mM) caused some stimulation of enzyme activity by release of activity from the microsomal fraction into the cytosol, but neither phosphatidylglycerol nor monoacyl phosphatidylethanolamine had an effect on activity or subcellular distribution. A decrease in soluble cytidylyltransferase protein concentrations was found in IAA-treated pea stems, but this was not sufficient to account for all of the decrease in cytidylyltransferase activity. A 50% inhibition of enzyme activity could be obtained with 0.2 mM-CMP, which indicated possible allosteric regulation. Similar inhibition was obtained with 1.5 mM-ATP, but other nucleotides had no effect. The cytidylyltransferase enzyme protein was not directly phosphorylated, and the inhibition with 1.5 mM-ATP occurred with the purified enzyme, thus excluding an obligatory mediation via a modulator protein. The results indicate that the cytosolic form of cytidylyltransferase is the most important in pea stem tissue and that the decrease in cytidylyltransferase activity in IAA-treated material appears to be brought about by several methods.

EFFECTS OF PROLONGED EXPOSURE TO GSM900 ELECTROMAGNETIC FIELDS ON ENZYME ACTIVITY IN LEAVES OF PEAS (PISUM SATIVUM L.)

2010 ◽  
Vol II (4) ◽  
pp. 109-114
Author(s):  
Margarita Kouzmanova ◽  
Milena Dimitrova ◽  
Daniela Dragolova ◽  
Gabriela Atanassova ◽  
Nikolai Atanassov
Keyword(s):  
Enzyme Activity ◽  
Pisum Sativum ◽  
Electromagnetic Fields ◽  
Prolonged Exposure ◽  
Pisum Sativum L

UDP-Glucose: Glucosyltransferase Activity Involved in the Biosynthesis of Flavonol Triglucosides in Pisum sativum L. Seedlings

1979 ◽  
Vol 34 (9-10) ◽  
pp. 738-741 ◽  
Author(s):  
Josie L. Shute ◽  
Pablo S. Jourdan ◽  
Richard L. Mansell
Keyword(s):  
Enzyme Activity ◽  
Pisum Sativum ◽  
Young Leaf ◽  
Uridine Diphosphate ◽  
First Report ◽  
Pisum Sativum L ◽  
Reaction Proceeds ◽  
Leaf Tissues

Abstract From young, light-grown seedlings of Pisum sativum L. an enzyme activity catalyzing the glucosylation of kaempferol and quercetin in the 3-position to form the 3-O-triglucoside derivative has been demonstrated. The reaction proceeds from the aglycone via the mono-and diglucoside intermediates. The triglucoside can be produced from any of the less substituted derivatives with uridine diphosphate-D-glucose (UDPG) as the glucosyl donor. Young leaf tissues had much high­er levels of glucosyltransferase activity than the petioles and internodes. This is the first report of the synthesis of flavonol-3-0-triglucosides in vitro.

scholarly journals Substrate specificities of the enzymes of the oleate desaturase system from photosynthetic tissue

1985 ◽  
Vol 225 (1) ◽  
pp. 267-270 ◽  
Author(s):  
D J Murphy ◽  
I E Woodrow ◽  
K D Mukherjee
Keyword(s):  
Pisum Sativum ◽  
Microsomal Fraction ◽  
Major Product ◽  
Acyl Transfer ◽  
Functional Coupling ◽  
Substrate Specificities ◽  
Oleate Desaturase ◽  
Pisum Sativum L ◽  
Bulk Membrane ◽  
Desaturase System

In the microsomal fraction from young pea (Pisum sativum L.) leaves, the oleoyl moieties from oleoyl-CoA are principally transferred to the sn-2 position of phosphatidylcholine by oleoyl-CoA:1-acyl-lysophosphatidylcholine acyltransferase. The major product of this acyl transfer is 1-palmitoyl(stearoyl)-2-oleoyl phosphatidylcholine. The 1-palmitoyl(stearoyl)-2-oleoyl phosphatidylcholine is subsequently converted into 1-palmitoyl(stearoyl)-2-linoleoyl phosphatidylcholine by the oleate desaturase complex without equilibrating with the bulk membrane phosphatidylcholine pool. Hence, both the acyl transfer to phosphatidylcholine and the subsequent desaturation of oleoyl moieties occur on the sn-2 position of phosphatidylcholine, and there is also a functional coupling of the acyltransferase and oleate desaturase.

scholarly journals Studies on Phytoalexins VII. Chemical Stimulation of Pisatin Formation in Pisum Sativum L.

1965 ◽  
Vol 18 (4) ◽  
pp. 803 ◽  
Author(s):  
Dawn R Perrin ◽  
IAM Cruickshank
Keyword(s):  
Pisum Sativum ◽  
Chemical Stimulation ◽  
Chemical Reagents ◽  
Pisum Sativum L ◽  
Stimulation Of

Chemical reagents were tested for their effectiveness to stimulate pisatin production in the endocarp of pea pods. The following compounds were found most active:

scholarly journals Adenylate cyclase activity in the parotid gland of the mouse after isoproterenol stimulation.

1979 ◽  
Vol 27 (10) ◽  
pp. 1317-1321 ◽  
Author(s):  
N W Revis ◽  
J P Durham
Keyword(s):  
Enzyme Activity ◽  
Adenylate Cyclase ◽  
Parotid Gland ◽  
Subcellular Distribution ◽  
Plasma Membranes ◽  
Cellular Membrane ◽  
Cyclase Activity ◽  
Lysosomal Fraction ◽  
Similar Decrease ◽  
Stimulation Of

Previous studies have described a decrease in the activity of adenylate cyclase in the parotid gland of isoproterenol-treated rats. In the present studies, a similar decrease was observed in mice treated with isoproterenol. Studies on the subcellular distribution of adenylate cyclase after isoproterenol stimulation of the parotid gland showed that enzyme activity was increased in the lysosomal fraction and decreased in the cellular membrane fractions. Cytochemical studies on the localization of adenylate cyclase in stimulated gland showed an increase in vesicles which contained enzyme activity and a decrease in activity at the luminal and plasma membranes. It is suggested, based on the present findings and results reported by other investigators, that after isoproterenol stimulation of the parotid gland, adenylate cyclase (along with excess membrane) is degraded by lysosomes. If this suggestion is true, then the observed decrease in adenylate cyclase would have a molecular explanation.

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