scholarly journals Passive diffusion of non-electrolytes across the lysosome membrane

1989 ◽  
Vol 261 (2) ◽  
pp. 451-456 ◽  
Author(s):  
G P Iveson ◽  
S J Bird ◽  
J B Lloyd
Keyword(s):  
Hydrogen Bonding ◽  
Rat Liver ◽  
Liver Homogenate ◽  
Inverse Correlation ◽  
Protection Method ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes ◽  
Lysosome Membrane ◽  
Free Activity

An osmotic-protection method has been used to study the permeability of rat liver lysosomes to 43 organic non-electrolytes of formula weights ranging from 62 to 1000. A lysosome-rich centrifugal fraction of rat liver homogenate was resuspended in an unbuffered 0.25 M solution of test solute, pH 7.0, and incubated at 25 degrees C for 60 min. The free and total activities of 4-methylumbelliferyl N-acetyl-beta-D-glucosaminidase were measured after incubation for 0, 30 and 60 min. Three patterns of results were seen. In pattern A the percentage free activity remained low throughout the 60 min incubation, indicating little or no solute entry into the lysosomes. In pattern B, the percentage free activity was initially low, but rose substantially during the incubation, indicating solute entry. In pattern C there was not even initial osmotic protection, indicating very rapid solute entry. The rapidity of solute entry into the lysosomes showed no correlation with the formula weight, but a perfect inverse correlation with the hydrogen-bonding capacity of the solutes. The results, which can be used to predict the ability of further compounds to cross the lysosome membrane by unassisted diffusion, are discussed in the context of metabolite and drug release from lysosomes in vivo.

scholarly journals Identification of targeting proteinase for rat α1-macroglobulin in vivo. Mast-cell tryptase is a major component of the α1-macroglobulin-proteinase complex endocytosed into rat liver lysosomes

1994 ◽  
Vol 298 (1) ◽  
pp. 79-85 ◽  
Author(s):  
A Tsuji ◽  
T Akamatsu ◽  
H Nagamune ◽  
Y Matsuda
Keyword(s):  
Mast Cell ◽  
Rat Liver ◽  
Cathepsin L ◽  
Deae Cellulose ◽  
Serine Proteinase ◽  
Mast Cell Tryptase ◽  
Diisopropyl Fluorophosphate ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes

The alpha 1-macroglobulin-proteinase complex endocytosed into rat liver lysosomes was purified by a series of column chromatographic steps on concanavalin A-Sepharose, Sephacryl S-300, DEAE-cellulose and TSK gel DEAE-5PW columns. The complex contained no detectable alpha 2-macroglobulin. Studies on the substrate specificity indicated that the complex had tryptase-like activities towards various synthetic substrates, but no elastase, chymotrypsin, cathepsin-B and cathepsin-L activities. The proteinase activity was completely inhibited by di-isopropyl fluorophosphate, leupeptin and antipain, indicating that the proteinase bound to alpha 1-macroglobulin is a serine proteinase. Two protein bands (62 and 59 kDa) of the complex were labelled with [3H]diisopropyl fluorophosphate and both bands cross-reacted with anti-(mast-cell tryptase)antibody. These results suggest that mast-cell tryptase is a major targeting proteinase for alpha 1-macroglobulin in vivo. The main alpha-macroglobulin-proteinase complex in the adjuvant-treated rats was also the alpha 1-macroglobulin-tryptase complex, even though the plasma level of alpha 2-macroglobulin was elevated.

scholarly journals On the localisation of d-tubocurarine in rat liver lysosomes in vivo by electron microscopy and subcellular fractionation

1975 ◽  
Vol 289 (3) ◽  
pp. 251-256 ◽  
Author(s):  
Jeanette G. Weitering ◽  
Gerard J. Mulder ◽  
Dirk K. F. Meijer ◽  
Wim Lammers ◽  
Maarten Veenhuis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Rat Liver ◽  
Subcellular Fractionation ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes

scholarly journals The effect of Trypan Blue, suramin and aurothiomalate on the breakdown of 125I-labelled albumin within rat liver lysosomes

1971 ◽  
Vol 121 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Malcolm Davies ◽  
J. B. Lloyd ◽  
F. Beck
Keyword(s):  
Rat Liver ◽  
Trypan Blue ◽  
Enzyme Inhibitors ◽  
Protein Hydrolysis ◽  
Particulate Carbon ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes

1. A fraction enriched in lysosomes was prepared by centrifugation from the livers of rats that had been injected 0.5h before death with 125I-labelled albumin. When suspended in sucrose-protected buffer, pH7.4, and incubated at 22°C for 2h, the particles progressively released iodotyrosine into the medium. Albumin digestion did not occur if the particles were subjected to treatments known to break lysosomes or if particles from uninjected rats were incubated in medium containing 125I-labelled albumin. It is concluded that the observed production of iodotyrosine results from protein hydrolysis within intact heterolysosomes. 2. Particles from rats pre-treated with Trypan Blue, suramin or aurothiomalate released iodotyrosine more slowly than controls. Since these compounds are enzyme inhibitors that concentrate in liver lysosomes after administration in vivo, their effect is ascribed to intralysosomal inhibition of proteolysis. The doses used did not decrease endocytosis of albumin into liver or cause increased lysosome breakage during incubation, thus allowing some alternative explanations of the decreased proteolysis to be eliminated. Particulate carbon, a non-inhibitor that also concentrates in lysosomes, did not affect albumin hydrolysis.

Effects of ATP on lysosomes: protection against hyperosmolar KCl

1983 ◽  
Vol 245 (1) ◽  
pp. C68-C73 ◽  
Author(s):  
R. C. Ruth ◽  
W. B. Weglicki
Keyword(s):  
Protective Effect ◽  
Rat Liver ◽  
Liver Lysosomes ◽  
Subsequent Exposure ◽  
Atp Analogues ◽  
Rat Liver Lysosomes ◽  
Free Activity ◽  
Reversible Nature ◽  
Damaging Effects

After incubation at 37 degrees C in isosmolar (200 mM) KCl, rat liver lysosomes are susceptible to damage caused by brief exposure to hyperosmolar (greater than 200 mM) KCl. Lysosomes that are exposed to hyperosmolar KCl do not undergo significant lysis as long as they are maintained at hyperosmolar conditions; however, they will lyse on being returned to lower osmolarities. If the hyperosmolar KCl-treated lysosomes are intermittently transferred into equally hyperosmolar sucrose, they no longer undergo lysis on subsequent exposure to lower osmolarities; this confirms the reversible nature of the hyperosmolar KCl-induced damage. Thus the hypothesis that the hyperosmolar KCl damage involves an isosmotic permeating of the lysosome by KCl appears reasonable. The increase caused by the hyperosmolar KCl in free activity of beta-N-acetyl-D-glucosaminidase is reduced by about 50% by ATP but not by ATP analogues. ATP protects provided that it is added either before, or simultaneously with, exposure of the lysosomes to hyperosmolar KCl. However, if the ATP is not added until the lysosomes are already in the presence of the hyperosmolar KCl, it does not reverse the damaging effects of the KCl even though actual lysis has not yet occurred at the time of the ATP addition. The protective effect is established very rapidly, because ATP added simultaneously with the addition of the hyperosmolar KCl protects to the same extent as does ATP added any time prior to the KCl addition. The protective effect requires Mg2+ and is not supported by Ca2+. Maximal protection is provided by 5 X 10(-4) M ATP. It is postulated that ATP protects lysosomes by reducing an increase in intralysosomal concentration of KCl, which occurs when incubated lysosomes are exposed to hyperosmolar KCl.

Stabilization of rat liver lysosomes by (+)-cyanidanol-3 in vivo

1975 ◽  
Vol 24 (8) ◽  
pp. 905-909 ◽  
Author(s):  
Paul Niebes ◽  
Gilbert Ponard
Keyword(s):  
Rat Liver ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes

scholarly journals The permeability of rat liver lysosomes to sugars. Evidence for carrier-mediated facilitated diffusion

1979 ◽  
Vol 178 (2) ◽  
pp. 361-366 ◽  
Author(s):  
K Docherty ◽  
G V Brenchley ◽  
C N Hales
Keyword(s):  
Rat Liver ◽  
Sugar Uptake ◽  
Facilitated Diffusion ◽  
Rate Difference ◽  
Temperature Range ◽  
Lysosomal Membranes ◽  
Sugar Specificity ◽  
Protection Method ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes

1. By the osmotic-protection method, the penetration of sugars through the rat liver lysosomal membranes was studied with a view of determining whether sugar uptake was by facilitated diffusion. 2. The following criteria for this type of transport were established: sugar specificity, the order of uptake being 2-deoxy-D-glucose less than D-glucose less than D-mannose less than D-galactose less than D-ribose less than 2-deoxy-D-ribose; stereospecificity, the uptake of L-glucose and L-ribose being 50% slower than their D-stereoisomers; inhibition by 1 MM-phlorrhizin and 1 M-cytochalastin B; competition between sugars for uptake, and a Q10 (rate difference over a 10 degrees C temperature range) for uptake of approx. 2.8. 3. It is proposed that sugar uptake into lysosomes from rat liver is by facilitated diffusion.

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