scholarly journals The mechanism of action of GTP on Ca2+ efflux from rat liver microsomal vesicles

1987 ◽  
Vol 244 (1) ◽  
pp. 87-92 ◽  
Author(s):  
A P Dawson ◽  
G Hills ◽  
J G Comerford
Keyword(s):  
Electron Microscopy ◽  
Light Scattering ◽  
Ethylene Glycol ◽  
Rat Liver ◽  
Mechanism Of Action ◽  
Vesicle Fusion ◽  
Fusion Process ◽  
Poly Ethylene Glycol ◽  
Rapid Production ◽  
Poly Ethylene

1. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]), if added before GTP, blocks both Ca2+ efflux promoted by GTP and the effect of GTP on enhancement of inositol 1,4,5-triphosphate (IP3)-promoted Ca2+ release from preloaded microsomal vesicles. If, however, GTP[S] is added after GTP, it does not reverse the Ca2+ efflux promoted by GTP, nor does it inhibit IP3-promoted Ca2+ release. 2. The effect of GTP in enhancing IP3-promoted Ca2+ release is maintained after washing the microsomal vesicles free of added GTP. After this treatment, enhancement of IP3-promoted Ca2+ efflux can be observed in the absence of poly(ethylene glycol). 3. Electron microscopy shows that during GTP treatment of microsomal vesicles there is rapid production of very large vesicular structures, apparently produced by fusion of smaller vesicles. 4. Light-scattering changes are detectable during the fusion process. 5. Both Ca2+ efflux promoted by GTP and the enhancement of IP3-promoted Ca2+ release seen in the presence of GTP can probably be attributed to GTP-dependent vesicle fusion.

scholarly journals Binding of ADP to rat liver cytosolic proteins and its influence on the ratio of free ATP/free ADP

1989 ◽  
Vol 259 (1) ◽  
pp. 117-124 ◽  
Author(s):  
S Mörikofer-Zwez ◽  
P Walter
Keyword(s):  
Ethylene Glycol ◽  
Rat Liver ◽  
Binding Sites ◽  
Dissociation Constants ◽  
Cellular Protein ◽  
Poly Ethylene Glycol ◽  
Cytosolic Proteins ◽  
Kd Values ◽  
Cytosolic Extract ◽  
Poly Ethylene

In a cytosolic extract from rat liver, the number and the concentration of ADP-binding sites as well as their dissociation constants were determined by using the rate-of-dialysis technique. Interfering cytosolic adenylate kinase was extracted from the cytosol by affinity chromatography on Ap5A-agarose, and remaining traces of enzyme activity were inhibited with (+)-catechin. Binding of ADP to cytosolic proteins was increased by poly(ethylene glycol) and decreased by EDTA. The effect of 0.1 mM-EDTA could be reversed by addition of equimolar concentrations of Mn2+ or Mg2+. In presence of 5% poly(ethylene glycol), added to increase local protein concentration, two binding sites for ADP were observed, with KD values of 1.9 microM (site I) and 10.8 microM (site II). The concentration of these binding sites, when extrapolated to cellular protein concentrations, were 30 microM (site I) and 114 microM (site II). It is concluded that a minimum of about 50% of total cytosolic ADP is bound to proteins, and that the ratio of free ATP/free ADP is at least twice that of total ATP/total ADP.

Reappearance of slow mode in mixtures of polyethylene glycol and poly(sodium methacrylate)

Soft Matter ◽  
2018 ◽  
Vol 14 (24) ◽  
pp. 5039-5047
Author(s):  
Ksenija Kogej ◽  
Jaka Štirn ◽  
Jurij Reščič
Keyword(s):  
Polyethylene Glycol ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Ethylene Glycol ◽  
Slow Mode ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Scattering Signal ◽  
Sodium Methacrylate

After addition of poly(ethylene glycol) to a solution of poly(sodium methacrylate), the slow-mode dynamic light scattering signal reappears.

scholarly journals Nanogels obtained by gamma radiation induced polymerization

Polimery ◽  
2021 ◽  
Vol 66 (9) ◽  
pp. 451-458
Author(s):  
Nur Fathin Amirah Shafie ◽  
Mohd Yusof Hamzah ◽  
Roshafima Rasit Ali
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Zeta Potential ◽  
Ethylene Glycol ◽  
Gamma Radiation ◽  
Biomedical Applications ◽  
Poly Ethylene Glycol ◽  
Glycol Diacrylate ◽  
Radiation Induced ◽  
Poly Ethylene

The influence of 2-(dimethylamino)ethyl methacrylate (DMAEMA) concentration on the temperature sensitivity of nanogels based on N-isopropylacrylamide (NIPAAM), poly(vinylpyrrolidone) (PVP), poly(ethylene glycol) diacrylate (PEGDA) by gamma radiation induced polymerization was investigated. Dynamic light scattering (DLS) and zeta potential measurements were used to characterize the nanogels. Temperature has been found to cause the nanogel particles to swell and shirnkage, allowing controlled dosing of the drug contained in capsules. The developed nanogels are promising materials with great potential for biomedical applications.

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