scholarly journals Orientation of glycoprotein galactosyltransferase and sialyltransferase enzymes in vesicles derived from rat liver Golgi apparatus.

1981 ◽  
Vol 89 (2) ◽  
pp. 246-255 ◽  
Author(s):  
B Fleischer
Keyword(s):  
Golgi Apparatus ◽  
Rat Liver ◽  
Three Dimensional ◽  
Small Molecular Weight ◽  
Protein Substrates ◽  
Molar Ratios ◽  
Golgi Vesicles ◽  
Luminal Side ◽  
Triton X ◽  
Cis And Trans

UDP-galactose: N-acetylglucosamine galactosyltransferase (GT) and CMP-sialic:desialylated transferrin sialyltransferse (ST) activities of rat liver Golgi apparatus are membrane-bound enzymes that can be released by treatment with Triton X-100. When protein substrates are used to assay these enzymes in freshly prepared Golgi vesicles, both activities are enhanced about eightfold by the addition of Triton X-100. When small molecular weight substrates are used, however, both activities are only enhanced about twofold by the addition of detergent. The enzymes remain inaccessible to large protein substrates even after freezing and storage of the Golgi preparation for 2 mo in liquid nitrogen. Accessibility to small molecular and weight substrates increases significantly after such storage. GT and ST activities in Golgi vesicles are not destroyed by treatment with trypsin, but are destroyed by this treatment if the vesicles are first disrupted with Triton X-100. Treatment of Golgi vesicles with low levels of filipin, a polyene antibiotic known to complex with cholesterol in biological membranes, also results in enhanced trypsin susceptibility of both glycosyltransferases. Maximum destruction of the glycosyltransferase activities by trypsin is obtained at filipin to total cholesterol weight ratios of approximately 1.6 or molar ratios of approximately 1. This level of filipin does not solubilize the enzymes but causes both puckering of Golgi membranes visible by electron microscopy and disruption of the Golgi vesicles as measured by release of serum albumin. When isolated Golgi apparatus is fixed with glutaraldehyde to maintain the three-dimensional orientation of cisternae and secretory vesicles, and then treated with filipin, cisternal membranes on both cis and trans faces of the apparatus as well as secretory granule membranes appear to be affected about equally. These results indicate that liver Golgi vesicles as isolated are largely oriented with GT and ST on the luminal side of the membranes, which corresponds to the cisternal compartment of the Golgi apparatus in the hepatocyte. Cholesterol is an integral part of the membrane of the Golgi apparatus and its distribution throughout the apparatus is similar to that of both transferases.

scholarly journals Passage of serum-destined proteins through the Golgi apparatus of rat liver. An examination of heavy and light Golgi fractions.

1978 ◽  
Vol 76 (1) ◽  
pp. 87-97 ◽  
Author(s):  
J J Bergeron ◽  
D Borts ◽  
J Cruz
Keyword(s):  
Golgi Apparatus ◽  
Rat Liver ◽  
Gel Electrophoresis ◽  
Intracellular Transport ◽  
Serum Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Secretory Protein ◽  
Pulse Injection ◽  
Cis And Trans ◽  
In Cis

The participation of hepatic Golgi apparatus in the intracellular transport of blood-destined proteins has been analyzed using Golgi fractions enriched in cis and trans components of the Golgi apparatus. SDS-polyacrylamide gel electrophoresis of the liver Golgi fractions showed several proteins corresponding in relative proportions and mobilities with serum proteins. After a pulse injection of labeled leucine, the secretory content of the cis Golgi fraction was labeled earlier than the trans Golgi fraction. Taken together, the results show the participation of the liver Golgi apparatus in the secretion of most of the serum proteins and provide documentation for a sequential progression of secretory protein through the cis and trans components of the Golgi apparatus.

scholarly journals The topographical location and unique nature of a glucokinase associated with the Golgi apparatus of rat liver

1976 ◽  
Vol 154 (1) ◽  
pp. 193-201 ◽  
Author(s):  
G Berthillier ◽  
R Coleman ◽  
D G Walker
Keyword(s):  
Golgi Apparatus ◽  
Rat Liver ◽  
Freezing And Thawing ◽  
Golgi Membranes ◽  
Unique Nature ◽  
Triton X

A particulate glucokinase was recovered in the Golgi-rich fraction of rat liver prepared by the method of Morré [Methods Enzymol. (1971) 22, 130-148], thus extending the demonstration by Berthillier et al. [Biochim. Biophys. Acta (1973), 293, 370-378] of particulate glucokinase activity in a microsomal subfraction that showed enrichment in Golgi characteristics. The purity of this fraction was examined and it was then subjected to several treatments, the action of Triton X-100, freezing and thawing, and sonication to establish the topographical location of the glucokinase activity thus solubilized. The evidence suggests that the glucokinase activity is either soluble in the lumen of the Golgi apparatus or loosely associated with the inside of the Golgi membranes.

scholarly journals Mannosyl carrier functions of retinyl phosphate and dolichyl phosphate in rat liver endoplasmic reticulum

1983 ◽  
Vol 210 (2) ◽  
pp. 541-547 ◽  
Author(s):  
K E Creek ◽  
D J Morré ◽  
C S Silverman-Jones ◽  
Y Shidoji ◽  
L M De Luca
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Rat Liver ◽  
Subcellular Fractions ◽  
Transfer Activity ◽  
Dolichyl Phosphate ◽  
Endoplasmic Reticulum Protein ◽  
Triton X

Of the subcellular fractions of rat liver the endoplasmic reticulum was the most active in GDP-mannose: retinyl phosphate mannosyl-transfer activity. The synthesis of retinyl phosphate mannose reached a maximum at 20-30 min of incubation and declined at later times. Retinyl phosphate mannose and dolichyl phosphate mannose from endogenous retinyl phosphate and dolichyl phosphate could also be assayed in the endoplasmic reticulum. About 1.8 ng (5 pmol) of endogenous retinyl phosphate was mannosylated per mg of endoplasmic reticulum protein (15 min at 37 degrees C, in the presence of 5 mM-MnCl2), and about 0.15 ng (0.41 pmol) of endogenous retinyl phosphate was mannosylated with Golgi-apparatus membranes. About 20 ng (13.4 pmol) of endogenous dolichyl phosphate was mannosylated in endoplasmic reticulum and 4.5 ng (3 pmol) in Golgi apparatus under these conditions. Endoplasmic reticulum, but not Golgi-apparatus membranes, catalysed significant transfer of [14C]mannose to endogenous acceptor proteins in the presence of exogenous retinyl phosphate. Mannosylation of endogenous acceptors in the presence of exogenous dolichyl phosphate required the presence of Triton X-100 and could not be detected when dolichyl phosphate was solubilized in liposomes. Dolichyl phosphate mainly stimulated the incorporation of mannose into the lipid-oligosaccharide-containing fraction, whereas retinyl phosphate transferred mannose directly to protein.

scholarly journals Isolation of a matrix that binds medial Golgi enzymes

1994 ◽  
Vol 124 (4) ◽  
pp. 405-413 ◽  
Author(s):  
P Slusarewicz ◽  
T Nilsson ◽  
N Hui ◽  
R Watson ◽  
G Warren
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Dissociation Constant ◽  
Rat Liver ◽  
Proteinase K ◽  
Apparent Dissociation Constant ◽  
Low Salt ◽  
The Matrix ◽  
Matrix Removal ◽  
Triton X

Rat liver Golgi stacks were extracted with Triton X-100 at neutral pH. After centrifugation the low speed pellet contained two medial-Golgi enzymes, N-acetylglucosaminyltransferase I and mannosidase II, but no enzymes or markers from other parts of the Golgi apparatus. Both were present in the same structures which appeared, by electron microscopy, to be small remnants of cisternal membranes. The enzymes could be removed by treatment with low salt, leaving behind a salt pellet, which we term the matrix. Removal of salt caused specific re-binding of both enzymes to the matrix, with an apparent dissociation constant of 3 nM for mannosidase II. Re-binding was abolished by pretreatment of intact Golgi stacks with proteinase K, suggesting that the matrix was present between the cisternae.

Golgi Apparatus and Melanogenesis: Ultrastructural Study of a Human Cellular Blue Nevus (Melanocytoma)

1973 ◽  
Vol 31 ◽  
pp. 380-381
Author(s):  
S.R. Allegra
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Ultrastructural Study ◽  
The Other ◽  
Blue Nevus ◽  
Normal Complement ◽  
Golgi Vesicles ◽  
Golgi System ◽  
The Subject ◽  
Cellular Blue Nevus

The respective roles of the ribo somes, endoplasmic reticulum, Golgi apparatus and perhaps nucleus in the synthesis and maturation of melanosomes is still the subject of some controversy. While the early melanosomes (premelanosomes) have been frequently demonstrated to originate as Golgi vesicles, it is undeniable that these structures can be formed in cells in which Golgi system is not found. This report was prompted by the findings in an essentially amelanotic human cellular blue nevus (melanocytoma) of two distinct lines of melanocytes one of which was devoid of any trace of Golgi apparatus while the other had normal complement of this organelle.

Fractionation of rat liver mitochondrial components after short treatments with triton x-100

1982 ◽  
Vol 14 (10) ◽  
pp. 933-940 ◽  
Author(s):  
M.C. Barbero ◽  
E. Rial ◽  
J.J. Otamendi ◽  
J.I.G. Gurtubay ◽  
F.M. Goni
Keyword(s):  
Rat Liver ◽  
Triton X
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