scholarly journals Effect of chelating agents and phosphoramidon on the L-leucine transport system in microvillar vesicles from pig kidney

FEBS Letters ◽  
1979 ◽  
Vol 101 (2) ◽  
pp. 407-410 ◽  
Author(s):  
A.John Kenny ◽  
David M. O'Halloran
Keyword(s):  
Transport System ◽  
Chelating Agents ◽  
Pig Kidney ◽  
Leucine Transport

scholarly journals Purification and characterization of pig kidney aminopeptidase P. A glycosyl-phosphatidylinositol-anchored ectoenzyme

1990 ◽  
Vol 267 (2) ◽  
pp. 509-515 ◽  
Author(s):  
N M Hooper ◽  
J Hryszko ◽  
A J Turner
Keyword(s):  
Chelating Agents ◽  
Inhibitory Effect ◽  
Purification And Characterization ◽  
Glycosyl Phosphatidylinositol ◽  
Pig Kidney ◽  
Sds Page ◽  
Cyclic Phosphate ◽  
Aminopeptidase P ◽  
Mild Acid

Aminopeptidase P (EC 3.4.11.9) was solubilized from pig kidney membranes with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) and then purified by a combination of anion-exchange and hydrophobic-interaction chromatographies. Contaminating peptidase activities were removed by selective affinity chromatography. The purified enzyme was apparently homogeneous on SDS/PAGE with an Mr of 91,000. Enzymic deglycosylation revealed that aminopeptidase P is a glycoprotein, with up to 25% by weight of the protein being due to the presence of N-linked sugars. The phospholipase-solubilized aminopeptidase P was recognized by an antiserum to the cross-reacting determinant (CRD) characteristic of the glycosyl-phosphatidylinositol anchor. This recognition was abolished by mild acid treatment or deamination with HNO2, indicating that the CRD was due exclusively to the inositol 1,2-cyclic phosphate ring epitope generated by the action of PI-PLC. The activity of aminopeptidase P was inhibited by chelating agents and was stimulated by Mn2+ or Co2+ ions, confirming the metallo-enzyme nature of this peptidase. Selective inhibitors of other aminopeptidases (actinonin, amastatin, bestatin and puromycin) had little or no inhibitory effect.

Leucine transport system in a facultatively alkalophilic Bacillus

1988 ◽  
Vol 262 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Kunitoshi Wakabayashi ◽  
Noriyuki Koyama ◽  
Yoshiaki Nosoh
Keyword(s):  
Transport System ◽  
Leucine Transport ◽  
Alkalophilic Bacillus

Modification of leucine transport across bovine pigment epithelium by metabolic stress

1989 ◽  
Vol 257 (5) ◽  
pp. C940-C947 ◽  
Author(s):  
E. L. Pautler ◽  
C. Tengerdy ◽  
J. Beyer ◽  
D. Beezley
Keyword(s):  
Transport System ◽  
Opposite Direction ◽  
Competitive Inhibition ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Metabolic Stress ◽  
Temperature Sensitive ◽  
Sodium Dependence ◽  
L System ◽  
Leucine Transport

The transport of leucine in the apical-to-basal (retina to choroid) direction across the isolated bovine retinal pigment epithelium is mediated predominantly by the L amino transport system at low carrier (10 microns) concentrations. There is no evidence of an active or facilitated transport system operating in the opposite direction. The identification of the L system is based on the lack of sodium dependence, specific inhibition of leucine transport by 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), and the demonstration of trans-stimulation. Lysine, glutamate, and 2-methylaminoisobutyric acid (MeAIB) did not provide any competitive inhibition. Ouabain and iodoacetate were also ineffective in modifying leucine transport. The transport mediated by the L system was markedly temperature sensitive, whereas no temperature dependence was apparent in the transport of leucine in the basal-to-apical direction (choroid to retina). When treated with dinitrophenol (DNP), the transport of leucine in the apical-to-basal direction was greatly enhanced, but no effect was observed on the leucine movement in the opposite direction. Azide and rotenone had an effect similar to DNP, as did reducing the partial pressure of O2 to less than 40 Torr. The enhancement of transport appeared to be mediated by the activation of an ancillary system, since it was susceptible to different classes of metabolic and competitive inhibitors as well as the observed ionic dependency. After DNP treatment, the transport of leucine was inhibited by lysine and BCH, revealed a sodium dependence, and could be inhibited by iodoacetate. The characteristics of the enhanced transport appear to be similar to those of the recently described G system(s) of amino acid transport.

Characterization of l-leucine transport system in brush border membranes from human and rabbit small intestine

Metabolism ◽  
1999 ◽  
Vol 48 (11) ◽  
pp. 1432-1436 ◽  
Author(s):  
P. Iannoli ◽  
J.H. Miller ◽  
H.T. Wang ◽  
B. Bode ◽  
W.W. Souba ◽  
...  
Keyword(s):  
Small Intestine ◽  
Transport System ◽  
Brush Border ◽  
Brush Border Membranes ◽  
Rabbit Small Intestine ◽  
Leucine Transport

scholarly journals Discrimination of two amino acid transport activities in 4F2 heavy chain- expressing Xenopus laevis oocytes

1998 ◽  
Vol 333 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Angelika BRÖER ◽  
Bernd HAMPRECHT ◽  
Stefan BRÖER
Keyword(s):  
Amino Acid ◽  
Transport System ◽  
Amino Acid Transport ◽  
Transport Systems ◽  
Xenopus Laevis Oocytes ◽  
Acid Transport ◽  
Transport Activity ◽  
Independent System ◽  
Leucine Transport ◽  
Dependent Transport

Expression of the type II membrane proteins of the rbAT/4F2hc family in Xenopus laevisoocytes results in the induction of amino acid transport activity. To elucidate the mechanism of action, amino acid transport was investigated in oocytes expressing the surface antigen 4F2hc. Leucine transport was mediated by a Na+-independent and a Na+-dependent transport mechanism. Both systems could be further discriminated by their stereochemical constraints. Isoleucine, with a branch at the β-position, shared only the Na+-independent transport system with leucine. Both transport systems were sensitive to inhibition by arginine, but only the Na+-independent system was sensitive to inhibition by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid. When compared with known transport systems the two transport activities could be described as similar to, but not identical with, mammalian systems b0,+ and y+L. The Na+-independent b0,+-like transport system was found both in rbAT and 4F2hc expressing oocytes, indicating that both proteins act in a similar way.

Surface aminopeptidase in Moniliformis dubius and its relation to amino acid uptake

Parasitology ◽  
1973 ◽  
Vol 67 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Gray L. Uglem ◽  
Peter W. Pappas ◽  
Clark P. Read
Keyword(s):  
Amino Acids ◽  
Transport System ◽  
Incubation Medium ◽  
Ambient Medium ◽  
Surface Membrane ◽  
Spatial Arrangement ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Leucine Uptake ◽  
Leucine Transport

Surface aminopeptidase (APase) in the acanthocephalan, Moniliformis dubius, was studied using leucylleucine, leucylglycylglycine, glycylglycine, alanylalanine, tri-alanine and tetra-alanine as substrates. In the presence of intact worms all peptides, except glycylglycine, were hydrolysed liberating amino acids and/or peptide subunits into the incubation medium. In 5 min incubations with 5mM leucylleucine, 93% of the liberated leucine was absorbed by the worms indicating a kinetic advantage for absorption of the leucine. In media with leucylleucine plus 10 mM methionine as an inhibitor of leucine uptake, the liberated leucine was not absorbed by the worms, but accumulated in the incubation medium. The inhibitory effects of leucylleucine and alanylalanine (or products of hydrolysis) on the uptake of 0·1 mM [14C]leucine in 2 min incubations were examined. Inhibition of [14C]leucine uptake by these peptides was non-linear up to 5 mM inhibitor concentration. Concentrations of either peptide greater than 5 mM did not produce further inhibition. A significant portion of [14C]leucine transport was not inhibited by these peptides. Inclusion of 0·5 mM Pb2+, an APase inhibitor, blocked the inhibition of [14C]leucine uptake by leucylleucine indicating that the inhibition is caused by the liberated leucine alone, and that interaction of the intact dipeptide and the leucine transport system is negligible. It is concluded that the surface membrane of adult worms has APase which can hydrolyse peptides in the ambient medium. The spatial arrangement of the APase and the leucine transport system is such that the hydrolysis of a peptide confers a kinetic advantage for absorption of the liberated amino acids. Encysted or mechanically excysted cystacanth larvae from the haemocoele of the cockroach showed no APase activity. Activation of the APase required a 30 min treatment in lipase, [Na+]taurocholate or other surface active agents. Since the APase in adult worms was unaffected by washing, the data strongly suggest that this enzyme is of parasitic origin.

Reconstitution of the leucine transport system of Lactococcus lactis into liposomes composed of membrane-spanning lipids from Sulfolobus acidocaldarius

Biochemistry ◽  
1992 ◽  
Vol 31 (49) ◽  
pp. 12493-12499 ◽  
Author(s):  
Gerda In't Veld ◽  
Marieke G. L. Elferink ◽  
Arnold J. M. Driessen ◽  
Wil N. Konings
Keyword(s):  
Lactococcus Lactis ◽  
Transport System ◽  
Sulfolobus Acidocaldarius ◽  
Leucine Transport ◽  
Membrane Spanning
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