A Functional Role for Histidyl Residues of the UDP-Glucuronic Acid Carrier in Rat Liver Endoplasmic Reticulum Membranes†

Biochemistry ◽  
1998 ◽  
Vol 37 (1) ◽  
pp. 258-263 ◽  
Author(s):  
Eric Battaglia ◽  
Anna Radominska-Pandya
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Functional Role ◽  
Glucuronic Acid

scholarly journals Two kinetically-distinct components of UDP-glucuronic acid transport in rat liver endoplasmic reticulum

1996 ◽  
Vol 1283 (2) ◽  
pp. 223-231 ◽  
Author(s):  
Eric Battaglia ◽  
Susan Nowell ◽  
Richard R. Drake ◽  
Magdalena Mizeracka ◽  
Carl L. Berg ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Glucuronic Acid ◽  
Acid Transport

Nuclear membrane-bound UDPglucuronosyltransferase of rat liver

1982 ◽  
Vol 60 (10) ◽  
pp. 972-979 ◽  
Author(s):  
Jan Zaleski ◽  
Surendra K. Bansal ◽  
Teresa Gessner
Keyword(s):  
Endoplasmic Reticulum ◽  
High Activity ◽  
Rat Liver ◽  
Nuclear Membrane ◽  
Glucuronic Acid ◽  
Microsomal Enzyme ◽  
Subcellular Membrane ◽  
Membrane Bound ◽  
Specific Activities

Some properties of rat liver nuclear membrane-bound UDPglucuronosyltransferase were compared with those of the endoplasmic reticulum bound enzyme. The activity of nuclear membrane-bound UDPglucuronosyltransferase was stimulated only about 1.5-fold by Lubrol WX. Under the same conditions microsomal UDPglucuronosyltransferase was, as usual, highly activated (up to 10-fold), when 4-nitrophenol was the acceptor of glucuronic acid. Specific activities of the detergent-activated enzyme were similar in microsomal and nuclear membrane preparations, when the following aglycone substrates were used: 4-methylumbelliferone, 4-nitrophenol, 1-naphthol, phenolphthalein, and testosterone. Apparent Km values for UDP-glucuronic acid ranged between 0.15–0.25 mM for glucuronidation of 4-nitrophenol and 1-naphthol, by either Lubrol WX activated or non-activated, nuclear membrane-bound UDPglucuronosyltransferase. These values were comparable to those found for detergent activated microsomal enzyme. The results show a similarity in behavior of detergent-activated UDPglucuronosyltransferase regardless of subcellular membrane source and, therefore, suggest the association of the same glucuronosyltransferase with nuclear membrane and endoplasmic reticulum. A possible significance of the presence of high activity of this enzyme in nuclear membrane is discussed.

scholarly journals Evidence for an UDP-glucuronic acid/phenol glucuronide antiport in rat liver microsomal vesicles

1996 ◽  
Vol 315 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Gábor BÁNHEGYI ◽  
László BRAUN ◽  
Paola MARCOLONGO ◽  
Miklós CSALA ◽  
Rosella FULCERI ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Glucuronic Acid ◽  
Udp Glucuronosyltransferase ◽  
Luminal Compartment ◽  
Loading Procedure ◽  
Stimulation Of

The transport of glucuronides synthesized in the luminal compartment of the endoplasmic reticulum by UDP-glucuronosyltransferase isoenzymes was studied in rat liver microsomal vesicles. Microsomal vesicles were loaded with p-nitrophenol glucuronide (5 mM), phenolphthalein glucuronide or UDP-glucuronic acid, by a freeze–thawing method. It was shown that: (i) the loading procedure resulted in millimolar intravesicular concentrations of the different loading compounds; (ii) addition of UDP-glucuronic acid (5 mM) to the vesicles released both intravesicular glucuronides within 1 min; (iii) glucuronides stimulated the release of UDP-glucuronic acid from UDP-glucuronic acid-loaded microsomal vesicles; (iv) trans-stimulation of UDP-glucuronic acid entry by loading of microsomal vesicles with p-nitrophenol glucuronide, phenolphthalein glucuronide, UDP-glucuronic acid and UDP-N-acetylglucosamine almost completely abolished the latency of UDP-glucuronosyltransferase, although mannose 6-phosphatase latency remained unaltered; (v) the loading compounds by themselves did not stimulate UDP-glucuronosyltransferase activity. This study indicates that glucuronides synthesized in the lumen of endoplasmic reticulum can leave by an antiport, which concurrently transports UDP-glucuronic acid into the lumen of the endoplasmic reticulum.

scholarly journals Carrier-mediated transport of intact UDP-glucuronic acid into the lumen of endoplasmic-reticulum-derived vesicles from rat liver

1994 ◽  
Vol 302 (1) ◽  
pp. 261-269 ◽  
Author(s):  
X Bossuyt ◽  
N Blanckaert
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Glucuronic Acid ◽  
Double Labelling ◽  
Carrier Mediated Transport ◽  
Cytosolic Side ◽  
Stimulation Experiments ◽  
Uptake Studies ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Uptake and metabolism of UDP-glucuronic acid (UDPGlcA) by rough-endoplasmic-reticulum (RER)-derived vesicles was studied. Analysis of the molecular species, double-labelling experiments and trans-stimulation experiments revealed that initial uptake represented entry into microsomes of predominantly intact UDPGlcA, concomitant with rapid hydrolysis of the internalized nucleotide sugar. The uptake constituted effective translocation from the medium into the lumen of the vesicles. Thus the amount of vesicle-associated label at equilibrium uptake was directly proportional to the volume of the intravesicular space. Permeabilized microsomes were unable to retain UDPGlcA. The microsomal uptake of UDPGlcA met the criteria of bidirectional carrier-mediated translocation. Transport was time- and temperature-dependent, saturable, selective, capable of trans-stimulation, and operational against a concentration gradient. Microsomal uptake was inhibited by N-ethylmaleimide that was presented at the cytosolic side of the endoplasmic-reticulum (ER) membrane. Uptake studies performed in membrane preparations that were highly enriched in RER, smooth ER or Golgi revealed that UDPGlcA was taken up by the ER as well as by the Golgi apparatus. Our findings demonstrate the existence in rat liver ER of a carrier system mediating proper translocation of intact UDPGlcA across the membrane.

scholarly journals Release of calcium from the endoplasmic reticulum by bile acids in rat liver cells.

1988 ◽  
Vol 263 (5) ◽  
pp. 2299-2303 ◽  
Author(s):  
L Combettes ◽  
M Dumont ◽  
B Berthon ◽  
S Erlinger ◽  
M Claret
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acids ◽  
Rat Liver ◽  
Liver Cells ◽  
Rat Liver Cells
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