scholarly journals Photoaffinity labelling of nucleoside-transport proteins in plasma membranes isolated from rat and guinea-pig liver

1984 ◽  
Vol 220 (2) ◽  
pp. 499-506 ◽  
Author(s):  
J S R Wu ◽  
J D Young
Keyword(s):  
Guinea Pig ◽  
Plasma Membranes ◽  
Species Difference ◽  
Sodium Dodecyl ◽  
Competitive Inhibitor ◽  
Nucleoside Transport ◽  
Nucleoside Transporter ◽  
Pig Liver ◽  
Liver Homogenates ◽  
Guinea Pig Liver

Nitrobenzylthioinosine (NBMPR) was employed as a probe of the nucleoside transporters from rat and guinea-pig liver. Purified liver plasma membranes prepared on self-generating Percoll density gradients exhibited 16-fold (rat) and 10-fold (guinea pig) higher [3H]NBMPR-binding activities than in crude liver homogenates (3.69 and 14.7 pmol/mg of protein for rat and guinea-pig liver membranes respectively, and 0.23 and 1.47 pmol/mg of protein for crude liver homogenates respectively). Binding to membranes from both species was saturable (apparent Kd 0.14 and 0.63 nM for rat and guinea-pig membranes respectively) and inhibited by uridine, adenosine, nitrobenzylthioguanosine (NBTGR) and dilazep. Uridine was an apparent competitive inhibitor of high-affinity NBMPR binding to rat membranes (apparent Ki 1.5 mM). There was a marked species difference with respect to dipyridamole inhibition of NBMPR binding (50% inhibition at 0.2 and greater than 100 microM for guinea-pig and rat respectively). These results are consistent with a role of NBMPR-binding proteins in liver nucleoside transport. Exposure of rat and guinea pig membranes to high-intensity u.v. light in the presence of [3H]NBMPR resulted in the selective radio-labelling of membrane proteins which migrated on sodium dodecyl sulphate/polyacrylamide gels with apparent Mr values in the same range as that of the human erythrocyte nucleoside transporter (45 000-66 000). Covalent labelling of these proteins was abolished when photolysis was performed in the presence of non-radio-active NBTGR as competing ligand.

Die Bedeutung der Homogenisationsart und -intensität für die Größe und Konstanz der Sauerstoffaufnahme von Meerschweinchen-Leberhomogenat / The Influence of Mode and Intensity of Homogenization on the Absolute Value and Stability of Oxygen Consumption of Guinea Pig Liver Homogenates

1977 ◽  
Vol 32 (11-12) ◽  
pp. 908-912 ◽  
Author(s):  
H. J. Schmidt ◽  
U. Schaum ◽  
J. P. Pichotka
Keyword(s):  
Oxygen Uptake ◽  
Guinea Pig ◽  
Measuring Time ◽  
Pig Liver ◽  
Absolute Value ◽  
Modified Method ◽  
Simultaneous Measurements ◽  
Liver Homogenates ◽  
The Absolute ◽  
Guinea Pig Liver

Abstract The influence of five different methods of homogenisation (1. The method according to Potter and Elvehjem, 2. A modification of this method called Potter S, 3. The method of Dounce, 4. Homogenisation by hypersonic waves and 5. Coarce-grained homogenisation with the “Mikro-fleischwolf”) on the absolute value and stability of oxygen uptake of guinea pig liver homogenates has been investigated in simultaneous measurements. All homogenates showed a characteristic fall of oxygen uptake during measuring time (3 hours). The modified method according to Potter and Elvehjem called Potter S showed reproducible results without any influence by homogenisation intensity.

scholarly journals COMPARISONS OF THE OXIDATION OF C19-HYDROXYSTEROIDS BY GUINEA PIG LIVER HOMOGENATES

1957 ◽  
Vol 224 (2) ◽  
pp. 811-818
Author(s):  
Charles D. Kochakian ◽  
Betty R. Carroll ◽  
Barbara Uhri
Keyword(s):  
Guinea Pig ◽  
Pig Liver ◽  
Liver Homogenates ◽  
Guinea Pig Liver

scholarly journals The transglutaminase in vascular cells and tissues could provide an alternate pathway for fibrin stabilization

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 702-709
Author(s):  
CS Greenberg ◽  
KE Achyuthan ◽  
MJ Borowitz ◽  
MA Shuman
Keyword(s):  
Guinea Pig ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Vascular Cells ◽  
Pig Liver ◽  
Alternate Pathway ◽  
Sds Page ◽  
Immunohistochemical Techniques ◽  
Plasmin Inhibitor ◽  
Guinea Pig Liver

A thrombin-independent transglutaminase (TG) has been identified in vascular cells and tissues from human, rabbit, rat, porcine, and bovine sources. The vascular TG had several properties that were similar but not identical to guinea pig liver TG. Both enzymes had similar chromatographic and electrophoretic properties, preferentially cross- linked the alpha-chains of fibrinogen, and reacted with polyclonal and monoclonal anti-guinea-pig liver TG antibodies. However, the TG from adult bovine aortic endothelial (ABAE) cells exhibited a novel Ca2+/Mg2+ dependence for enzymatic activity that was distinct from that of purified guinea pig liver TG. The mol wt of the vascular TG (79 +/- 3 kd) determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was slightly lower than the purified guinea pig liver TG (85 +/- 9 kd). The TG antigen was detected by immunohistochemical techniques in association with the endothelial and smooth muscle cells of arteries, veins, venules, and capillaries. The TG antigen also codistributed with the fibronectin antigen along the hepatic sinusoids. The ABAE cell TG cross-linked alpha 2-plasmin inhibitor to fibrinogen and caused the modified fibrinogen to be 40- fold more resistant to plasminolysis. A thrombin-independent TG in vascular cells of blood vessels could provide an alternate pathway to inhibit fibrinolysis and promote fibrin stabilization.

scholarly journals Hydrolysis of a naturally occurring β-glucoside by a broad-specificity β-glucosidase from liver

1986 ◽  
Vol 237 (2) ◽  
pp. 469-476 ◽  
Author(s):  
K L LaMarco ◽  
R H Glew
Keyword(s):  
Guinea Pig ◽  
Competitive Inhibitor ◽  
Heat Denaturation ◽  
Pig Liver ◽  
Naturally Occurring ◽  
Aryl Glycosides ◽  
Beta Glucosidase ◽  
Hydrolysis Of ◽  
Guinea Pig Liver ◽  
Broad Specificity

We have isolated from guinea-pig liver a broad-specificity beta-glucosidase of unknown function that utilizes as its substrate non-physiological aryl glycosides (e.g. 4-methylumbelliferyl beta-D-glucopyranoside, p-nitrophenyl beta-D-glucopyranoside). The present paper documents that this enzyme can be inhibited by various naturally occurring glycosides, including L-picein, dhurrin and glucocheirolin. In addition, L-picein, which acts as a competitive inhibitor of the broad-specificity beta-glucosidase (Ki 0.65 mM), is also a substrate for this enzyme (Km 0.63 mM; Vmax. 277,000 units/mg). Heat-denaturation, kinetic competition studies, chromatographic properties and pH optima all argue strongly that the broad-specificity beta-glucosidase is responsible for the hydrolysis of both the non-physiological aryl glycosides and L-picein. This paper demonstrates that beta-glucosidase can catalyse the hydrolysis of a natural glycoside, and may provide a key to understanding the function of this enigmatic enzyme. A possible role in the metabolism of xenobiotic compounds is discussed.

Glucosiduronidation of 15α-hydroxyestrogens by guinea pig liver homogenates

Steroids ◽  
1972 ◽  
Vol 19 (4) ◽  
pp. 535-547 ◽  
Author(s):  
H. Jirku ◽  
S. Kadner ◽  
M. Levitz
Keyword(s):  
Guinea Pig ◽  
Pig Liver ◽  
Liver Homogenates ◽  
Guinea Pig Liver

scholarly journals Phosphoenolpyruvate carboxykinase from guinea-pig liver mitochondria. Immunological evidence for increase in enzyme amount during neonatal development

1984 ◽  
Vol 221 (1) ◽  
pp. 105-111 ◽  
Author(s):  
S Wicheanvonagoon ◽  
I J Arinze
Keyword(s):  
Guinea Pig ◽  
Sodium Dodecyl Sulphate ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Sodium Dodecyl ◽  
Protein Band ◽  
Liver Mitochondria ◽  
Polyacrylamide Gels ◽  
Neonatal Development ◽  
Pig Liver ◽  
Guinea Pig Liver

Phosphoenolpyruvate carboxykinase was purified from mitochondria of guinea-pig liver by affinity chromatography on GMP-Sepharose. The enzyme was purified 100-fold to a high degree of electrophoretic homogeneity as judged by detection of a single protein band on sodium dodecyl sulphate/polyacrylamide gels. The yield was about 16%. The Mr of the purified enzyme was estimated to be 68500 +/- 680 by analysis on sodium dodecyl sulphate/polyacrylamide gels. Antibodies raised in rabbits against the purified enzyme were highly specific for mitochondrial phosphoenolpyruvate carboxykinase and did not precipitate the cytosolic form of this enzyme from either rat or guinea-pig liver cytosol. The use of this antibody showed that starvation does not increase the amount of the enzyme. However, neonatal-development-dependent increase in its activity is shown to be mediated by accumulation of phosphoenol pyruvate carboxykinase-specific protein.

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