scholarly journals Oligosaccharide-based Surfactant/Citric Acid Buffer System Stabilizes Lactate Dehydrogenase during Freeze-drying and Storage without the Addition of Natural Sugar

2016 ◽  
Vol 65 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Shigesaburo Ogawa ◽  
Ryuichiro Kawai ◽  
Maito Koga ◽  
Kouichi Asakura ◽  
Isao Takahashi ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Citric Acid ◽  
Freeze Drying ◽  
Buffer System ◽  
Acid Buffer ◽  
Citric Acid Buffer ◽  
Acid Buffer System ◽  
And Storage

scholarly journals The bivalent-cation dependence of phosphatidylinositol synthesis in a cell-free system from lymphocytes

1983 ◽  
Vol 212 (3) ◽  
pp. 691-697 ◽  
Author(s):  
J P Moore ◽  
G A Smith ◽  
T R Hesketh ◽  
J C Metcalfe
Keyword(s):  
Citric Acid ◽  
Phosphatidic Acid ◽  
Bivalent Cation ◽  
Free System ◽  
Cell Free System ◽  
Acid Buffer ◽  
Physiological Conditions ◽  
Citric Acid Buffer ◽  
A Cell

The bivalent-cation requirements of two enzymes involved in phosphatidylinositol synthesis were defined for pig lymphocyte membranes using a citric acid buffer. CTP:phosphatidic acid cytidylyltransferase (EC 2.7.7.41) is activated by free Mn2+ concentrations above 20nM and by free Mg2+ concentrations above 10 microM. When activated by Mg2+, the enzyme is weakly inhibited by Ca2+ (Ki greater than 250 microM), but Ca2+ has no effect when Mn2+ is used to stimulate CDP-diacylglycerol synthesis. The synthesis of phosphatidylinositol from phosphatidic acid is also stimulated by Mn2+ and Mg2+ concentrations similar to those above and is inhibited by free Ca2+ concentrations above 500nM, probably by its action on CDP-diacylglycerol:inositol 3-phosphatidyltransferase (EC 2.7.8.11). Taken together, these studies suggest that under physiological conditions phosphatidylinositol synthesis is activated by Mg2+ and it is possible that it is further regulated by the free concentrations of Ca2+ and/or Mn2+.

Leukocyte β-Galactosidase Activity in GM1-Gangliosidosis

PEDIATRICS ◽  
1972 ◽  
Vol 50 (3) ◽  
pp. 502-503
Author(s):  
Elisabeth Young ◽  
R. B. Ellis ◽  
A. D. Patrick
Keyword(s):  
Citric Acid ◽  
Recent Article ◽  
Galactosidase Activity ◽  
Alternative Substrate ◽  
Gm1 Gangliosidosis ◽  
Acid Buffer ◽  
Assay Medium ◽  
Routine Service ◽  
Citric Acid Buffer ◽  
Beta Galactosidase

The recent article by Singer et al. entitled "Leukocyte beta-Galactosidase Activity in the Diagnosis of Generalized GM1-Gangliosidosis," prompts us to report the results of two years of routine service assay of this enzyme in leukocytes using the alternative substrate, 4-methyl-umbelliferyl β-D-galactopyranoside. The β-galactosidase assay medium contained McIlvaine phosphate-citric acid buffer, pH, 4.1 (40µl); 4-methylumbelliferyl β-D-galactopyranoside (1 mM in buffer, 150µl) and leukocyte extract in 0.2 MKCl (10µl). After incubation for 15 minutes at 30°C, the reaction was stopped by the addition of 0.25 M glycine-NaOH, pH, 10.4 (1 ml) and the fluorescence measured.

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