scholarly journals Lysosomal enzyme phosphorylation. Recognition of a protein-dependent determinant allows specific phosphorylation of oligosaccharides present on lysosomal enzymes.

1984 ◽  
Vol 259 (23) ◽  
pp. 14663-14671 ◽  
Author(s):  
L Lang ◽  
M Reitman ◽  
J Tang ◽  
R M Roberts ◽  
S Kornfeld
Keyword(s):  
Lysosomal Enzyme ◽  
Lysosomal Enzymes

scholarly journals Secretion of β-N-acetylglucosaminidase isoenzymes by normal human fibroblasts

1978 ◽  
Vol 173 (2) ◽  
pp. 433-439 ◽  
Author(s):  
P Willcox
Keyword(s):  
Lysosomal Enzyme ◽  
Human Fibroblast ◽  
Lysosomal Enzymes ◽  
Culture Medium ◽  
Human Fibroblasts ◽  
The Other ◽  
Normal Human Fibroblast ◽  
Acid Hydrolases ◽  
Human Fibroblast Cultures ◽  
Normal Human

1. Secretion of the lysosomal enzyme beta-N-acetylglucosaminidase (EC 3.2.1.30) by normal human fibroblast cultures was linear with respect to time up to 96h. 2. Two forms of the A isoenzyme of beta-N-acetylglucosaminidase were found in the culture medium. One form was similar to the isoenzyme found in other extracellular fluids, such as plasma and tears, the other resembled the intracellular (lysosomal) enzyme. The presence of the two isoenzymes in the culture medium appears to reflect two distinct secretory processes. 3. It is suggested that plasma acid hydrolases may be destined for incorporation into lysosomes in a manner analogous to that described for the packaging of lysosomal enzymes by fibroblasts.

Microtubule modulation of biliary excretion of endogenous and exogenous hepatic lysosomal constituents

1984 ◽  
Vol 246 (1) ◽  
pp. G8-G15 ◽  
Author(s):  
R. B. Sewell ◽  
S. S. Barham ◽  
A. R. Zinsmeister ◽  
N. F. LaRusso
Keyword(s):  
Lysosomal Enzyme ◽  
Biliary Excretion ◽  
Lysosomal Enzymes ◽  
Male Rats ◽  
Enzyme Secretion ◽  
Initial Increase ◽  
Acute Administration ◽  
Subsequent Decrease ◽  
Before And After

We tested the hypothesis that hepatocyte microtubules modulate the biliary excretion of endogenous and exogenous constituents of hepatocyte lysosomes. We collected bile via bile fistulas from male rats before and after acute administration of colchicine and vinblastine, agents known to bind to hepatocyte microtubules; rats were then killed and livers were homogenized for biochemical analyses or processed for electron microscopy. Colchicine caused biphasic, parallel alterations in the biliary excretion of three lysosomal enzymes compared with control rats given saline or lumicolchicine; a peak rise in enzyme outputs of approximately 175% at 45-60 min after colchicine administration was followed by a sustained fall to approximately 25% of control values, which persisted for 2-4 h. When hepatocyte lysosomes were prelabeled in vivo by administration of [3H]Triton WR-1339, a nonionic detergent that is sequestered in hepatic lysosomes, the biliary excretion of radiolabel in response to colchicine paralleled the biliary excretion of the three lysosomal enzymes. Vinblastine also induced a biphasic response in biliary lysosomal enzyme output that was similar to that produced by colchicine administration. Morphometric analysis of electron micrographs of rat livers demonstrated changes in the number of lysosomelike vesicles in the vicinity of bile canaliculi after colchicine and vinblastine administration; the initial increase in lysosomal enzyme secretion was associated with a significant decrease in the number of pericanalicular lysosomes after both agents, while the subsequent decrease in enzyme secretion coincided with an increase in the number of pericanalicular lysosomes after vinblastine.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Specific alterations in levels of mannose 6-phosphorylated glycoproteins in different neuronal ceroid lipofuscinoses

1998 ◽  
Vol 334 (3) ◽  
pp. 547-551 ◽  
Author(s):  
David E. SLEAT ◽  
Istvan SOHAR ◽  
Premila S. PULLARKAT ◽  
Peter LOBEL ◽  
Raju K. PULLARKAT
Keyword(s):  
Lysosomal Enzyme ◽  
Neurodegenerative Disorders ◽  
Enzyme Activities ◽  
Lysosomal Enzymes ◽  
Vesicular Transport ◽  
Cell Types ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Mannose 6 Phosphate ◽  
Normal Controls ◽  
Lysosomal Proteins

Mannose 6-phosphate (Man-6-P) is a carbohydrate modification that is generated on newly synthesized lysosomal proteins. This modification is specifically recognized by two Man-6-P receptors that direct the vesicular transport of the lysosomal enzymes from the Golgi to a prelysosomal compartment. The Man-6-P is rapidly removed in the lysosome of most cell types; however, in neurons the Man-6-P modification persists. In this study we have examined the spectrum of Man-6-P-containing glycoproteins in brain specimens from patients with different neuronal ceroid lipofuscinoses (NCLs), which are progressive neurodegenerative disorders with established links to defects in lysosomal catabolism. We find characteristic alterations in the Man-6-P glycoproteins in specimens from late-infantile (LINCL), juvenile (JNCL) and adult (ANCL) patients. Man-6-P glycoproteins in LINCL patients were similar to controls, with the exception that the band corresponding to CLN2, a recently identified lysosomal enzyme whose deficiency results in this disease, was absent. In an ANCL patient, two Man-6-P glycoproteins were elevated in comparison with normal controls, suggesting that this disease also results from a perturbation in lysosomal hydrolysis. In JNCL, total levels of Man-6-P glycoproteins were 7-fold those of controls. In general this was reflected by increased lysosomal enzyme activities in JNCL but three Man-6-P glycoproteins were elevated to an even greater degree. These are CLN2 and the unidentified proteins that are also highly elevated in the ANCL.

scholarly journals The role of lysosomal enzymes in killing of mammalian cells by the lysosomotropic detergent N-dodecylimidazole.

1987 ◽  
Vol 104 (5) ◽  
pp. 1223-1229 ◽  
Author(s):  
P D Wilson ◽  
R A Firestone ◽  
J Lenard
Keyword(s):  
Cell Viability ◽  
Ammonium Chloride ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Human Fibroblasts ◽  
Cysteine Proteases ◽  
Cytotoxic Agents ◽  
Cysteine Cathepsins ◽  
Cathepsin Activity ◽  
Cysteine Cathepsin

The sensitivity of cultured human and hamster fibroblast cells to killing by the lysosomotropic detergent N-dodecylimidazole (C12-Im) was investigated as a function of cellular levels of general lysosomal hydrolase activity, and specifically of cysteine cathepsin activity. Fibroblasts from patients with mucolipidosis II (I-cell disease) lack mannose-6-phosphate-containing proteins, and therefore possess only 10-15% of the normal level of most lysosomal hydrolases. I-cell fibroblasts are about one-half as sensitive to killing by C12-Im as are normal human fibroblasts. Overall lysosomal enzyme levels of CHO cells were experimentally manipulated in several ways without affecting cell viability: Growth in the presence of 10 mM ammonium chloride resulted in a gradual decrease in lysosomal enzyme content to 10-20% of control values within 3 d. Subsequent removal of ammonium chloride from the growth medium resulted in an increase in lysosomal enzymes, to approximately 125% of control values within 24 h. Treatment with 80 mM sucrose caused extensive vacuolization within 2 h; lysosomal enzyme levels remained at control levels for at least 6 h, but increased 15-fold after 24 h of treatment. Treatment with concanavalin A (50 micrograms/ml) also caused rapid (within 2 h) vacuolation with a sevenfold rise in lysosomal enzyme levels occurring only after 24 h. The sensitivity of these experimentally manipulated cells to killing by C12-Im always paralleled the measured intracellular lysosomal enzyme levels: lower levels were associated with decreased sensitivity while higher levels were associated with increased sensitivity, regardless of the degree of vacuolization of the cells. The cytotoxicity of the cysteine proteases (chiefly cathepsin L in our cells) was tested by inactivating them with the irreversible inhibitor E-64 (100 micrograms/ml). Cell viability, protein levels, and other lysosomal enzymes were unaffected, but cysteine cathepsin activity was reduced to less than 20% of control values. E-64-treated cells were almost completely resistant to C12-Im treatment, although lysosomal disruption appeared normal by fluorescent visualization of Lucifer Yellow CH-loaded cells. It is concluded that cysteine cathepsins are the major or sole cytotoxic agents released from lysosomes by C12-Im. These observations also confirm the previous conclusions that C12-Im kills cells as a consequence of lysosomal disruption.

The Induction of Lysosomal Enzyme Release from Leucocytes of Normal and Emphysematous Subjects and the Effects of Tobacco Smoke upon Phagocytosis

1980 ◽  
Vol 58 (5) ◽  
pp. 403-409 ◽  
Author(s):  
D. C. S. Hutchison ◽  
R. Desai ◽  
D. Bellamy ◽  
H. Baum
Keyword(s):  
Cigarette Smoke ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Soluble Fraction ◽  
Normal Subjects ◽  
Polymorphonuclear Leucocytes ◽  
Enzyme Release ◽  
Elastic Tissue ◽  
Latex Particles ◽  
Respiratory Inhibitor

1. The lysosomal enzymes of circulating polymorphonuclear leucocytes contain a potent elastase; release of this enzyme within the lung is thought to be responsible for the destruction of elastic tissue in pulmonary emphysema. 2. The release of lysosomal enzymes from blood leucocytes of normal and emphysematous subjects during phagocytosis of particulate material was studied In vitro. Acid phosphatase and acid ribonuclease were used as markers of lysosomal enzyme release, no sufficiently sensitive assay for elastase being available. Cigarette smoke was separated into ‘particulate’ and ‘soluble’ fractions. In a preliminary study, the particulate fraction stimulated enzyme release; in the experiments reported here, latex particles were used to produce this effect. 3. Approximately one-third of the total lysosomal enzyme content was released to the exterior of the cell during phagocytosis of latex particles. In this respect there was no difference between normal and emphysematous subjects. 4. The effects of the non-particulate soluble fraction of cigarette smoke on phagocytosis-induced enzyme release were studied. This fraction inhibited enzyme release from polymorphonuclear leucocytes of normal subjects but not from those of emphysematous patients. When the ‘cigarette-smoke solution’ was replaced by the respiratory inhibitor, antimycin A, a similar inhibition of enzyme release occurred. The inhibition of phagocytosis in cells of normal subjects is presumed to be due to a respiratory inhibitor such as carbon monoxide in the soluble fraction of the smoke. We postulate that the polymorphonuclear leucocytes of emphysematous patients are adapted to hypoxic conditions so that inhibition of enzyme release does not occur.

scholarly journals Clathrin heavy chain functions in sorting and secretion of lysosomal enzymes in Dictyostelium discoideum.

1994 ◽  
Vol 126 (2) ◽  
pp. 343-352 ◽  
Author(s):  
T Ruscetti ◽  
J A Cardelli ◽  
M L Niswonger ◽  
T J O'Halloran
Keyword(s):  
Dictyostelium Discoideum ◽  
Heavy Chain ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Secretory Pathway ◽  
Chain Gene ◽  
Wild Type ◽  
Clathrin Heavy Chain ◽  
Mutant Cells

The clathrin heavy chain is a major component of clathrin-coated vesicles that function in selective membrane traffic in eukaryotic cells. We disrupted the clathrin heavy chain gene (chcA) in Dictyostelium discoideum to generate a stable clathrin heavy chain-deficient cell line. Measurement of pinocytosis in the clathrin-minus mutant revealed a four-to five-fold deficiency in the internalization of fluid-phase markers. Once internalized, these markers recycled to the cell surface of mutant cells at wild-type rates. We also explored the involvement of clathrin heavy chain in the trafficking of lysosomal enzymes. Pulse chase analysis revealed that clathrin-minus cells processed most alpha-mannosidase to mature forms, however, approximately 20-25% of the precursor molecules remained uncleaved, were missorted, and were rapidly secreted by the constitutive secretory pathway. The remaining intracellular alpha-mannosidase was successfully targeted to mature lysosomes. Standard secretion assays showed that the rate of secretion of alpha-mannosidase was significantly less in clathrin-minus cells compared to control cells in growth medium. Interestingly, the secretion rates of another lysosomal enzyme, acid phosphatase, were similar in clathrin-minus and wild-type cells. Like wild-type cells, clathrin-minus mutants responded to starvation conditions with increased lysosomal enzyme secretion. Our study of the mutant cells provide in vivo evidence for roles for the clathrin heavy chain in (a) the internalization of fluid from the plasma membrane; (b) sorting of hydrolase precursors from the constitutive secretory pathway to the lysosomal pathway; and (c) secretion of mature hydrolases from lysosomes to the extracellular space.

scholarly journals Mannosidosis in Galloway Calves

1985 ◽  
Vol 22 (6) ◽  
pp. 548-551 ◽  
Author(s):  
D. H. Embury ◽  
I. V. Jerrett
Keyword(s):  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Lysosomal Storage ◽  
Normal Tissues ◽  
Liver And Kidney ◽  
The Central Nervous System ◽  
Gross Lesions ◽  
Renal Tubular ◽  
Histologic Changes ◽  
The Brain

Mannosidosis was diagnosed in four stillborn Galloway calves and an autolyzed full-term fetus from experimental matings of carrier animals. Gross lesions were moderate internal hydrocephalus, and pallor and enlargement of the liver and kidneys and arthrogryposis. Histologic changes in the central nervous system of each calf were marked foamy vacuolation of the cytoplasm of neurones in the cerebral cortex, thalamus and brainstem, and vacuolation of the Purkinje cells of the cerebellum. Spheroids were common throughout the brain and there was also consistent severe foamy cytoplasmic vacuolation of renal tubular epithelial cells and hepatocytes. The activities of α-mannosidase, the lysosomal enzyme whose activity is deficient in mannosidosis, and activities of five other lysosomal enzymes were compared in brain, liver, and kidney tissues of three mannosidosis-affected calves and normal calf tissues. Tissues from the affected calves had a marked deficiency of α-mannosidase activity compared with the normal tissues; the greatest deficiency was in the liver (99%) and brain (98%). Activities of the other lysosomal enzymes were elevated in the affected tissues compared with normal. Mannosidosis is a lysosomal storage disease that results from a defect in glycoprotein metabolism and affects man,18 Angus and Angus-related breeds of cattle, such as Murray greys,12,21 and the cat.4 The congenital disease is caused by an inherited deficiency of the lysosomal enzyme α-mannosidase,14 and is inherited in an autosomal recessive manner. Mannosidosis was recently reported in a number of aborted and stillborn Australian Galloway calves3 from an experimental breeding trial. This is more detailed account of the histological and biochemical results obtained during the trial.

scholarly journals Inhibition by cyanate of the processing of lysosomal enzymes

1983 ◽  
Vol 210 (3) ◽  
pp. 795-802 ◽  
Author(s):  
A Hasilik ◽  
R Pohlmann ◽  
K von Figura
Keyword(s):  
Golgi Apparatus ◽  
Lysosomal Enzyme ◽  
Cathepsin D ◽  
Lysosomal Enzymes ◽  
Intracellular Transport ◽  
Human Fibroblasts ◽  
Cultured Human Fibroblasts ◽  
High Mannose ◽  
In Cells

In cultured human fibroblasts, maturation of the lysosomal enzymes beta-hexosaminidase and cathepsin D is inhibited by 10 mM-potassium cyanate. In cells treated with cyanate the two enzymes accumulate in precursor forms. The location of the accumulated precursor is probably non-lysosomal; in fractionation experiments the precursors separate from the bulk of the beta-hexosaminidase activity. The secretion of the precursor of cathepsin D, but not that of beta-hexosaminidase precursor, is enhanced in the presence of cyanate. The secreted cathepsin D, as well as that remaining within the cells, contains mostly high-mannose oligosaccharides cleavable with endo-beta-N-acetylglucosaminidase H. After removal of cyanate, the accumulated precursor forms of the lysosomal enzymes are largely released from the pretreated cells. It is concluded that cyanate interferes with the maturation of lysosomal-enzyme precursors by perturbing their intracellular transport. Most probably cyanate affects certain functions of the Golgi apparatus.

scholarly journals Proteolytische Aktivitäten der lysosomalen Enzyme bei Milchrindern* – 1. Mitteilung: Variation der lysosomalen Enzyme bei Milchkühen

1999 ◽  
Vol 42 (4) ◽  
pp. 321-334
Author(s):  
L. Panicke ◽  
M. Schmidt ◽  
T. Król ◽  
R. Staufenbiel
Keyword(s):  
Dairy Cattle ◽  
Lysosomal Enzyme ◽  
Enzyme Activities ◽  
Lysosomal Enzymes ◽  
Milk Traits ◽  
Additional Information ◽  
Milk Performance ◽  
Proteolytic Activities ◽  
Fertility Traits ◽  
Daily Milk

Abstract. Titel of the paper: Proteolytic activities of lysosomal enzymes in dairy cattle. I. Variation of lysosomal enzymes in dairy cattle There are no references to be found in the literature dealing with genetic aspects of lysosomal enzyme activities m blood of dairy cows, The used amino peptidases are connected to the proteolysis. 1011 investigated cows showed Variation coefficients of ≈50%, higher than in milk traits In simultaneous samples it reduces to 20–30% similar to daily milk samples The heritability coefficients h2 = 0,10–0,20 is approximately between fertility traits and milk traits The investigation of lysosomal enzyme activities might be limited to plasma. No additional information could be gained using the leukocytes. Changing activities of enzymes in plasma are aqually directed to the milk performance. It may be concluded that the trait spectrum might be reduced to DP-IV, AGR, ALA, AGLD and EL as well especially to protein yield of milk.

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