scholarly journals Difference in kinetic properties between hexokinase type I isoenzymes from various rat tissues with reference to the effect of a thiol inhibitor (Short Communication)

1974 ◽  
Vol 137 (1) ◽  
pp. 139-142 ◽  
Author(s):  
T. Kamikashi ◽  
H. Kizaki ◽  
K. Murakami ◽  
S. Ishibashi
Keyword(s):  
Short Communication ◽  
Kinetic Studies ◽  
Kinetic Properties ◽  
Rat Tissues ◽  
Type I ◽  
Different Tissues ◽  
Hexokinase Type I

Hexokinase isoenzyme type I was purified from various rat tissues, and was subjected to kinetic studies in the presence or the absence of p-chloromercuribenzenesulphonate. The mode of the inhibition by the thiol inhibitor was different for the type I isoenzymes obtained from different tissues, suggesting that the type I isoenzymes from different tissues were not identical proteins.

scholarly journals Kinetic properties and tissular distribution of mammalian phosphomannomutase isozymes

1999 ◽  
Vol 339 (1) ◽  
pp. 201-207 ◽  
Author(s):  
Michel PIRARD ◽  
Younes ACHOURI ◽  
Jean-François COLLET ◽  
Els SCHOLLEN ◽  
Gert MATTHIJS ◽  
...  
Keyword(s):  
Kinetic Studies ◽  
Time Dependent ◽  
Chemical Characteristics ◽  
Kinetic Properties ◽  
Rat Tissues ◽  
Northern Blots ◽  
Carbohydrate Deficient Glycoprotein Syndrome ◽  
Fructose 1,6 Bisphosphate ◽  
Acyl Phosphate ◽  
Stimulation Of

Human tissues contain two types of phosphomannomutase, PMM1 and PMM2. Mutations in the PMM2 gene are responsible for the most common form of carbohydrate-deficient glycoprotein syndrome [Matthijs, Schollen, Pardon, Veiga-da-Cunha, Jaeken, Cassiman and Van Schaftingen (1997) Nat. Genet.19, 88–92]. The protein encoded by this gene has now been produced in Escherichia coli and purified to homogeneity, and its properties have been compared with those of recombinant human PMM1. PMM2 converts mannose 1-phosphate into mannose 6-phosphate about 20 times more rapidly than glucose 1-phosphate to glucose 6-phosphate, whereas PMM1 displays identical Vmax values with both substrates. The Ka values for both mannose 1,6-bisphosphate and glucose 1,6-bisphosphate are significantly lower in the case of PMM2 than in the case of PMM1. Like PMM1, PMM2 forms a phosphoenzyme with the chemical characteristics of an acyl-phosphate. PMM1 and PMM2 hydrolyse different hexose bisphosphates (glucose 1,6-bisphosphate, mannose 1,6-bisphosphate, fructose 1,6-bisphosphate) at maximal rates of ≈ 3.5 and 0.3% of their PMM activity, respectively. Fructose 1,6-bisphosphate does not activate PMM2 but causes a time-dependent stimulation of PMM1 due to the progressive formation of mannose 1,6-bisphosphate from fructose 1,6-bisphosphate and mannose 1-phosphate. Experiments with specific antibodies, kinetic studies and Northern blots indicated that PMM2 is the only detectable isozyme in most rat tissues except brain and lung, where PMM1 accounts for about 66 and 13% of the total activities, respectively.

scholarly journals Purification of the hexokinases by affinity chromatography on sepharose-N-aminoacylglucosamine derivates. Design of affinity matrices from free solution kinetics

1978 ◽  
Vol 175 (1) ◽  
pp. 125-135 ◽  
Author(s):  
C L Wright ◽  
A S Warsy ◽  
M J Holroyde ◽  
I P Trayer
Keyword(s):  
Affinity Chromatography ◽  
Kinetic Properties ◽  
Type I ◽  
Type Ii ◽  
Free Solution ◽  
Affinity Matrix ◽  
Type Iii ◽  
Ability To Act ◽  
Affinity Techniques ◽  
Hexokinase Type I

The purification is described of rat hepatic hexokinase type III and kidney hexokinase type I on a large scale by using a combination of conventional and affinity techniques similar to those previously used for the purification of rat hepatic glucokinase [Holroyde, Allen, Storer, Warsy, Chesher, Trayer, Cornish-Bowden & Walker (1976) Biochem. J. 153, 363-373] and muscle hexokinase type II [Holroyde & Trayer (1976) FEBS Lett. 62, 215-219]. The key to each purification was the use of a Sepharose-N-aminoacylglucosamine affinity matrix in which a high degree of specificity for a particular hexokinase isoenzyme could be introduced by either varying the length of the aminoacyl spacer and/or varying the ligand concentration coupled to the gel. This was predicted from a study of the free solution kinetic properties of the various N-aminoacylglucosamine derivatives used (N-aminopropionyl, N-aminobutyryl, N-aminohexanoyl and N-aminooctanoyl), synthesized as described by Holroyde, Chesher, Trayer & Walker [(1976) Biochem. J. 153, 351-361]. All derivatives were competitive inhibitors, with respect to glucose, of the hexokinase reaction, and there was a direct correlation between the Ki for a particular derivative and its ability to act as an affinity matrix when immobilized to CNBr-activated Sepharose 4B. Muscle hexokinase type II could be chromatographed on the Sepharose conjugates of all four N-aminoacylglucosamine derivatives, although the N-aminohexanoylglucosamine derivative proved best. This same derivative was readily able to bind hepatic glucokinase and hexokinase type III, but Sepharose-N-amino-octanoyl-glucosamine was better for these enzymes and was the only derivative capable of binding kidney hexokinase type I efficiently. Separate studies with yeast hexokinase showed that again only the Sepharose-N-amino-octanoylglucosamine was capable of acting as an efficient affinity matrix for this enzyme. Implications of these studies in our understanding of affinity-chromatography operation are discussed.

Differential expression of type-specific c-abl mRNAs in mouse tissues and cell lines

1988 ◽  
Vol 8 (10) ◽  
pp. 4547-4551
Author(s):  
M W Renshaw ◽  
M A Capozza ◽  
J Y Wang
Keyword(s):  
Alternative Splicing ◽  
Differential Expression ◽  
Cell Lines ◽  
Relative Abundance ◽  
Cell Types ◽  
Type I ◽  
Rnase Protection ◽  
Type Iv ◽  
Mouse Tissues ◽  
Different Tissues

The mammalian c-abl proto-oncogene produces mRNAs with 5' heterogeneity from two distinct promoters and the alternative splicing of variable 5' exons. By using quantitative RNase protection assays, the relative abundance of two major c-abl mRNAs, type I and type IV, in several mouse tissues and cell lines has been determined. Our results demonstrate that the level of type IV c-abl mRNA is rather constant, whereas that of the type I mRNA varies over a 10-fold range in different tissues and cell types. This finding has interesting implications for the function of the two c-abl proteins.

Integrin (alpha) and beta subunit contribution to the kinetic properties of (alpha)2beta1 collagen receptors on human keratinocytes analyzed under hydrodynamic conditions

1999 ◽  
Vol 112 (14) ◽  
pp. 2335-2345 ◽  
Author(s):  
B. Masson-Gadais ◽  
A. Pierres ◽  
A.M. Benoliel ◽  
P. Bongrand ◽  
J.C. Lissitzky
Keyword(s):  
Type I Collagen ◽  
Human Keratinocytes ◽  
Flow Chamber ◽  
Dissociation Rate ◽  
Ligand Recognition ◽  
Kinetic Properties ◽  
Type I ◽  
Functional Region ◽  
Laminin 5 ◽  
Bond Stability

The adhesion of keratinocytes to type I collagen or laminin 5 was studied in a laminar flow chamber. These experiments provided an insight into the binding kinetics of integrins in their natural environment and the effects of monoclonal antibodies specific for (alpha) and beta chains. Cells driven by a force too low to alter the natural lifetime of a single bond displayed multiple arrests. Studying the frequency and duration of these arrests yielded fairly direct information on the rate of bond formation (on-rate) and dissociation (off-rate). Off-rate values obtained on collagen or laminin 5 (0.06 seconds-1) were tenfold lower than values determined on selectins. Bond stability was strongly regulated by anti-beta1 chain antibodies since the off-rate was decreased sixfold by activating antibody TS2/16 and increased fivefold by inhibitory antibodies Lia1/2 or P4C10, whereas neutral antibody K20 had no effect on this parameter. Binding frequencies were not significantly changed by all these antibodies. In contrast, both binding frequency and off-rate were altered by antibodies specific for the (alpha)2 chain, suggesting that these antibodies interfered with ligand recognition and also with the ligand-beta1 chain interactions responsible for bond stabilization. The latter hypothesis was supported by the finding that the partial alteration of (alpha)2 chain function by inhibiting antibodies was corrected by anti-beta1 chain antibody TS2/16. These results could not be ascribed to allosteric changes of the functional region of beta1 integrin subunits regulated by TS2/16 since there was no competition between the binding of TS2/16 and anti-(alpha)2 chain antibodies. Interpreted within the framework of current concepts of integrin-ligand binding topology, these data suggest that ligand-alpha chain interactions may be qualitatively important in ligand recognition and also influence the formation of the ligand-beta1 subunit bonding involved in stabilization of the ligand-integrin complex by regulating its dissociation rate.

K depletion modifies the properties of Sch-28080-sensitive K-ATPase in rat collecting duct

1997 ◽  
Vol 272 (1) ◽  
pp. F124-F131 ◽  
Author(s):  
B. Buffin-Meyer ◽  
M. Younes-Ibrahim ◽  
C. Barlet-Bas ◽  
L. Cheval ◽  
S. Marsy ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Rat Kidney ◽  
Lower Sensitivity ◽  
Kinetic Properties ◽  
Type I ◽  
Type Ii ◽  
Distribution Profile ◽  
Adenosine Triphosphatases ◽  
Collecting Ducts ◽  
K Depletion

Two distinct Sch-28080-sensitive K-adenosine triphosphatases (K-ATPases) were previously described in the rat nephron: a ouabain-resistant K-ATPase (type I) present in collecting ducts (CD) and a ouabain-sensitive from (type II) located in proximal tubules (PT) and thick ascending limbs (TAL). In K-depleted rats, K-ATPase activity is increased in CD, whereas it is reduced in PT and TAL. Because expression of colonic H-K-ATPase is restricted to the CD of K-depleted rats, we hypothesized that K-ATPase from the CD of K-depleted rats might be different from types I and II. Indeed, type III K-ATPase displays higher sensitivities to ouabain and to Sch-28080 than type II, a lower sensitivity to Sch-28080 than type I, and, conversely to types I and II, it can be stimulated by Na+. Pharmacological differences between types II and III K-ATPases were confirmed by [3H]ouabain binding experiments. Thus the rat kidney expresses three K-ATPases that differ by their pharmacological and kinetic properties, their distribution profile along the nephron and their behavior during K depletion.

scholarly journals Biochemical and Histopathological Alterations in Different Tissues of Rats Due to Repeated Oral Dose Toxicity of Cymoxanil

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2205
Author(s):  
Mohamed S. Ahmed ◽  
Ahmed H. Massoud ◽  
Aly S. Derbalah ◽  
Ashraf Al-Brakati ◽  
Mohsin A. Al-Abdawani ◽  
...  
Keyword(s):  
Toxicity Assessment ◽  
Significant Inhibition ◽  
High Dose ◽  
Rat Tissues ◽  
Biochemical Alterations ◽  
Histopathological Alterations ◽  
Piecemeal Necrosis ◽  
Oral Doses ◽  
Dose Dependent ◽  
Different Tissues

Evaluating potential adverse health impacts caused by pesticides is an important parameter in human toxicity. This study focuses on the importance of subchronic toxicity assessment of cymoxanil fungicide in rats with special reference to target biochemical enzymes and histopathological changes in different tissues. In this regard, a 21-day toxicity study with repeated cymoxanil oral doses was conducted. It has been shown that low doses (0.5 mg/kg) were less effective than medium (1 mg/kg) and high (2 mg/kg) doses. Moreover, high dose dose-treated rats showed piecemeal necrosis in the liver, interstitial nephritis and tubular degeneration in the kidneys, interstitial pneumonia and type II pneumocyte hyperplasia in the lungs, gliosis, spongiosis, and malacia in the brain, and testicular edema and degeneration in the testes. Cymoxanil significantly increased AST, ALT, and ALP in serum and liver, indicating tissue necrosis and possible leakage of these enzymes into the bloodstream. Creatinine levels increased, indicating renal damage. Similarly, significant inhibition was recorded in brain acetylcholinesterase, indicating that both synaptic transmission and nerve conduction were affected. Importantly, these histopathological and biochemical alterations were dose-dependent. Taken together, our study reported interesting biochemical and histopathological alterations in different rat tissues following repeated toxicity with oral doses of cymoxanil. Our study suggests future studies on different pesticides at different concentrations that would help urge governments to create more restrictive regulations concerning these compounds’ levels.

Purification, properties, and evidence for two subtypes of human placenta hexokinase type I

1988 ◽  
Vol 260 (1) ◽  
pp. 388-399 ◽  
Author(s):  
Mauro Magnani ◽  
Vilberto Stocchi ◽  
Giordano Serafini ◽  
Laura Chiarantini ◽  
Giorgio Fornaini
Keyword(s):  
Human Placenta ◽  
Type I ◽  
Hexokinase Type I

High resolution of multiple forms of rabbit reticulocyte hexokinase type I by hydrophobic interaction chromatography

1994 ◽  
Vol 676 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Vilberto Stocchi ◽  
Paola Cardoni ◽  
Paola Ceccaroli ◽  
Giovanni Piccoli ◽  
Luigi Cucchiarini ◽  
...  
Keyword(s):  
High Resolution ◽  
Hydrophobic Interaction ◽  
Hydrophobic Interaction Chromatography ◽  
Type I ◽  
Multiple Forms ◽  
Hexokinase Type I

Mitochondrial bound hexokinase type I in normal and streptozotocin diabetic rat retina

Mitochondrion ◽  
2020 ◽  
Vol 52 ◽  
pp. 212-217
Author(s):  
Gabriela Ramírez-Pérez ◽  
Gustavo Sánchez-Chávez ◽  
Rocío Salceda
Keyword(s):  
Diabetic Rat ◽  
Type I ◽  
Rat Retina ◽  
Streptozotocin Diabetic Rat ◽  
Hexokinase Type I
Sign in / Sign up

Export Citation Format

Share Document