scholarly journals Defective acid hydrolase secretion inRUNX1haplodeficiency: Evidence for a global platelet secretory defect

Haemophilia ◽  
2017 ◽  
Vol 23 (5) ◽  
pp. 784-792 ◽  
Author(s):  
A. K. Rao ◽  
M. Poncz
Keyword(s):  
Acid Hydrolase

scholarly journals Effects of antimycin A and 2-deoxyglucose on secretion in human platelets. Differential inhibition of the secretion of acid hydrolases and adenine nucleotides

1979 ◽  
Vol 182 (2) ◽  
pp. 413-419 ◽  
Author(s):  
Holm Holmsen ◽  
Linda Robkin ◽  
H. James Day
Keyword(s):  
Shape Change ◽  
Adenine Nucleotides ◽  
Human Platelets ◽  
Dense Granule ◽  
Metabolic Inhibitors ◽  
Antimycin A ◽  
Acid Hydrolase ◽  
Acid Hydrolases ◽  
Dense Granule Secretion ◽  
Granule Secretion

1. Shape change, aggregation and secretion of dense-granule constituents in platelets differ in their dependence on cellular energy metabolism. The possibility that such a difference also exists between secretion of dense-granule constituents and acid hydrolases was investigated. 2. Human platelets were incubated with [14C]adenine in plasma, and then washed and resuspended in salt solutions. The effects of incubating the cells with antimycin A and 2-deoxyglucose on the concentrations of [14C]ATP, ADP, AMP, IMP and inosine plus hypoxanthine and on thrombin-induced secretion of ATP plus ADP and acid hydrolases were studied. The metabolic inhibitors only affected 14C-labelled nucleotides, whereas thrombin only liberated unlabelled ATP and ADP. 3. The extent of secretion decreased progressively with time during incubation with the metabolic inhibitors. At any time the secretion of acid hydrolases, β-N-acetylglucosaminidase, β-glucuronidase and β-galactosidase was inhibited to a greater extent than secretion of ATP plus ADP (dense-granule secretion). 4. Incubation with the metabolic inhibitors shifted the log (dose)–response relationship to higher thrombin concentrations, and with a greater shift for acid hydrolase secretion than for dense-granule secretion. 5. Antimycin, when present alone, caused a marked decrease in the rate of acid hydrolase secretion, but had no effect on dense-granule secretion. 6. These results further support the view that acid hydrolase secretion and dense-granule secretion are separate processes with different requirements for ATP energy. Acid hydrolase secretion, but not dense-granule secretion, appears to depend on a simultaneous rapid generation of ATP, which can be accomplished by oxidative, but not by glycolytic, ATP production.

scholarly journals Plasmid Localization and Organization of Melamine Degradation Genes in Rhodococcus sp. Strain Mel

2011 ◽  
Vol 78 (5) ◽  
pp. 1397-1403 ◽  
Author(s):  
Anthony G. Dodge ◽  
Lawrence P. Wackett ◽  
Michael J. Sadowsky
Keyword(s):  
454 Pyrosequencing ◽  
Minimal Medium ◽  
Doubling Time ◽  
Cyanuric Acid ◽  
Acid Hydrolase ◽  
Content Type ◽  
N Source ◽  
Genes Encoding ◽  
Rhodococcus Sp ◽  
Roche 454

ABSTRACTRhodococcussp. strain Mel was isolated from soil by enrichment and grew in minimal medium with melamine as the sole N source with a doubling time of 3.5 h. Stoichiometry studies showed that all six nitrogen atoms of melamine were assimilated. The genome was sequenced by Roche 454 pyrosequencing to 13× coverage, and a 22.3-kb DNA region was found to contain a homolog to the melamine deaminase genetrzA. Mutagenesis studies showed that the cyanuric acid hydrolase and biuret hydrolase genes were clustered together on a different 17.9-kb contig. Curing and gene transfer studies indicated that 4 of 6 genes required for the complete degradation of melamine were located on an ∼265-kb self-transmissible linear plasmid (pMel2), but this plasmid was not required for ammeline deamination. TheRhodococcussp. strain Mel melamine metabolic pathway genes were located in at least three noncontiguous regions of the genome, and the plasmid-borne genes encoding enzymes for melamine metabolism were likely recently acquired.

Acetylsalicylic acid hydrolase of gastric mucosa.

1978 ◽  
Vol 234 (6) ◽  
pp. E606
Author(s):  
J G Spenney
Keyword(s):  
Gastric Mucosa ◽  
Enzymatic Activity ◽  
Acetylsalicylic Acid ◽  
Sodium Dodecyl ◽  
Sodium Cholate ◽  
Acid Hydrolase ◽  
Sulfhydryl Reagents ◽  
Ph Optimum ◽  
Diisopropyl Fluorophosphate

Acetylsalicylic acid hydrolase activity of rabbit fundic gastric mucosa has been isolated from the soluble 100,000 X g supernate. The enzymatic activity was partially purified by ammonium sulfate precipitation. The Km for acetylsalicylate was 2 mM and pH optimum was 8.6. The activity was insensitive to ionic strength, slightly inhibited by inclusion of 100 mM Cl-, and demonstrated no requirement for Ca2+ or Mg2+. Acetylsalicylic acid esterase was markedly inhibited by sodium cholate and sodium dodecyl sulfate. The enzyme was insensitive to sulfhydryl reagents with the exception of p-chloromercuribenzenesulfonic acid, which markedly inhibited the enzyme. Diisopropyl fluorophosphate (DFP) inhibited enzymatic activity with a Ki of 9 X 10(-9)M. Eserine was also inhibitory with a Ki of 0.25 mM. Inhibition by DFP at low concentration and by eserine at millimolar concentrations suggests that this enzyme is related to the group of aliphatic esterases. Identification of potent inhibitors will enable studies to define the role of this enzyme with the use of experimental preparations in which systemic toxicity can be avoided.

Temperature stability of proteins essential for the intracellular survival of Mycobacterium tuberculosis

2009 ◽  
Vol 418 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Nathan A. Lack ◽  
Akane Kawamura ◽  
Elizabeth Fullam ◽  
Nicola Laurieri ◽  
Stacey Beard ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cholesterol Metabolism ◽  
Specific Activity ◽  
Temperature Stability ◽  
Heat Stability ◽  
Dienoic Acid ◽  
Dramatic Reduction ◽  
Acid Hydrolase ◽  
Catabolic Pathway

In Mycobacterium tuberculosis, the genes hsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) and nat (arylamine N-acetyltransferase) are essential for survival inside of host macrophages. These genes act as an operon and have been suggested to be involved in cholesterol metabolism. However, the role of NAT in this catabolic pathway has not been determined. In an effort to better understand the function of these proteins, we have expressed, purified and characterized TBNAT (NAT from M. tuberculosis) and HsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) from M. tuberculosis. Both proteins demonstrated remarkable heat stability with TBNAT and HsaD retaining >95% of their activity after incubation at 60 °C for 30 min. The first and second domains of TBNAT were demonstrated to be very important to the heat stability of the protein, as the transfer of these domains caused a dramatic reduction in the heat stability. The specific activity of TBNAT was tested against a broad range of acyl-CoA cofactors using hydralazine as a substrate. TBNAT was found to be able to utilize not just acetyl-CoA, but also n-propionyl-CoA and acetoacetyl-CoA, although at a lower rate. As propionyl-CoA is a product of cholesterol catabolism, we propose that NAT could have a role in the utilization of this important cofactor.

scholarly journals Lymphocyte Lysosomes and Lysosomal Enzymes in Chronic Lymphocytic Leukemia

Blood ◽  
1973 ◽  
Vol 41 (4) ◽  
pp. 511-518 ◽  
Author(s):  
Steven D. Douglas ◽  
Georg Cohnen ◽  
Erika KÖnig ◽  
GÜnter Brittinger
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Microscopic Level ◽  
Lymphocytic Leukemia ◽  
Electron Microscopic Level ◽  
Acid Hydrolase ◽  
Electron Microscopic ◽  
Normal Cells ◽  
Biochemical Studies ◽  
Cell Profile

Abstract Electron microscopic cytochemical and biochemical studies of lysosomal markers have been performed in unstimulated normal and chronic lymphotic leukemia (CLL) lymphocytes. Decreased activities of the lysosomal enzymes acid phosphatase and β-glucuronidase but not of the nonlysosomal enzyme malate dehydrogenase were observed in CLL lymphocytes as compared to normal cells. At the electron microscopic level, the number of membrane-bounded acid phosphatase-positive organelles was diminished in CLL cells. (Average 1.07 per cell profile in normal cells and 0.17 in CLL lymphocytes). The findings indicate that the diminution of acid hydrolase activities in CLL lymphocytes is most likely due to a reduced number of lysosomes, rather than to a diminished enzyme content of these organelles.

scholarly journals Multivesicular endosomes containing internalized EGF-EGF receptor complexes mature and then fuse directly with lysosomes.

1996 ◽  
Vol 132 (6) ◽  
pp. 1011-1023 ◽  
Author(s):  
C E Futter ◽  
A Pearse ◽  
L J Hewlett ◽  
C R Hopkins
Keyword(s):  
Membrane Protein ◽  
Direct Contact ◽  
Egf Receptor ◽  
Multivesicular Bodies ◽  
Transferrin Receptors ◽  
Acid Hydrolase ◽  
Receptor Complexes ◽  
Mannose 6 Phosphate ◽  
Multivesicular Endosomes

We have followed the transfer of EGF-EGF receptor (EGFR) complexes from endosomal vacuoles that contain transferrin receptors (TfR) to lysosome vacuoles identified by their content of HRP loaded as a 15-min pulse 4 h previously. We show that the HRP-loaded lysosomes are lysosomal-associated membrane protein-1 (LAMP-1) positive, mannose-6-phosphate receptor (M6PR) negative. and contain active acid hydrolase. EGF-EGFR complexes are delivered to these lysosomes intact and are then rapidly degraded. Preactivating the HRP contained within the preloaded lysosomes inhibits the delivery of EGFR and degradation of EGF, and results in the accumulation of EGFR-containing multivesicular bodies (MVB). With time these accumulating MVB undergo a series of maturation changes that include the loss of TfR, the continued recruitment of EGFR, and the accumulation of internal vesicles, but they remain LAMP-1 and M6PR negative. The mature MVB are often seen to make direct contact with lysosomes containing preactivated HRP, but their perimeter membranes remain intact. Together our observations suggest that the transfer of EGF-EGFR complexes from the TfR-containing endosome compartment to the lysosomes that degrade them employs a single vacuolar intermediate, the maturing MVB, and can be achieved by a single heterotypic fusion step.

Evaluating metal ion salts as acid hydrolase mimics: metal-assisted hydrolysis of phospholipids at lysosomal pH

BioMetals ◽  
2012 ◽  
Vol 25 (6) ◽  
pp. 1207-1219 ◽  
Author(s):  
Sarah S. Cepeda ◽  
Dominique E. Williams ◽  
Kathryn B. Grant
Keyword(s):  
Metal Ion ◽  
Acid Hydrolase ◽  
Lysosomal Ph ◽  
Hydrolysis Of

Acid Hydrolase Activity in Osteoarthritic and Normal Human Cartilage

1973 ◽  
Vol 55 (5) ◽  
pp. 1068-1076 ◽  
Author(s):  
MICHAEL G. EHRLICH ◽  
HENRY J. MANKIN ◽  
BENJAMIN V. TREADWELL
Keyword(s):  
Hydrolase Activity ◽  
Acid Hydrolase ◽  
Human Cartilage ◽  
Normal Human

REQUIREMENT FOR THROMBIN RECEPTOR OCCUPANY DURING PLATELET SECRETION UNDER AGGREGATING CONDITIONS

1987 ◽  
Author(s):  
Kazuo Koike ◽  
Holm Holmsen
Keyword(s):  
Receptor Occupancy ◽  
Dense Granule ◽  
Secretory Process ◽  
Thrombin Receptor ◽  
Cell Contact ◽  
Acid Hydrolase ◽  
High Concentration ◽  
Dense Granule Secretion ◽  
Granule Secretion ◽  
Platelet Secretion

We have previously showed that hirudin abruptly arrests thrombin-induced secretion of acid hydrolase at any stage of its progress, whereas it only affects dense granule secretion only at its initial stages; these results have been interpreted to show that acid hydrolase secretion requires sustained while dense granule secreion ony requires a brief receptor occupancy (Holmsen et al. JBC 256(1981)9393). The requirement for receptor occupancy in thrombin-induced α-granule secretion and secretion during aggregation have been studied. Increasing concentrations of thrombin were added to gel-fitered platelets containing a constant, high concentration of hirudin. Dense granule secretion was initiated at lower thrombin concentration than those required for α-granule secretion and aggregation; acid hydrolase secretion required higher concentrations. A 14-fold exess of hirudin produced abrupt stop of dense granule secretion and α-granule secretion when added to platelets shortly after thrombin; it had no affect after these secretory process had reached 30% of their maximal values. Acid hydrolase secretion was, however, abruptly stopped by hirudin at any stage. When the platelets were allowed to aggregate, all three secretory processes increased their rates and could now be abruptly stopped by hirudin at any stage. Aggregation (optical) occurred slower than dense granule andoαgranule secretion, and was reversed by hirudin when added before it had reached 30% of its maximum. It is concluded thatαgranule secretion, like dense granule secretion, only requires a short receptor occupancy to be completed, in contrast to the requirement for sustained occupancy for hydrolase secretion.α-granule secretion might, however, require longer occupancy than dense granule secretion. It is possible that aggregation potentiates all secretory responses through close cell contact and that the abrupt inhibition by hirudin of all secretions may have been caused by its effect on the slower aggregation.

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