Determination of phosphate: Study of labile organic phosphate interference

Baginski, Eugene S.; Foà, Piero P.; Zak, Bennie

doi:10.1016/0009-8981(67)90340-3

Cited by 391 publications

(145 citation statements)

References 7 publications

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“…Tyrosine phosphate phosphatase activity was determined on L-tyrosine phosphate according to Apostol et al 1111. 470 Dephosphorylation of L-phosphoserine and L-phosphothreonine was measured by the method of Baginski [12].…”

Section: Phosphoamino Acid Phosphatase Activitymentioning

confidence: 99%

The 18 kDa cytosolic acid phosphatase from bovine liver has phosphotyrosine phosphatase activity on the autophosphorylated epidermal growth factor receptor

et al. 1989

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In this paper we demonstrate that the cytosolic low-M~ acid phosphatase purified from bovine liver has phosphotyrosine protein phosphatase acitivity on aep-autophosphorylated epidermal growth factor (EGF) receptor. This activity was significantly inhibited by orthovanadate and p-hydroxymercuribenzoate; the latter result indicates that free sulfhydryl groups are required for phosphotyrosine phosphatase activity. The enzyme was active in a broad pH range, with maximum activity between pH 5.5 and 7.5. The apparent Km for 32P-EGF receptor dephosphorylation was 4 riM. The enzyme appeared to be specific for phosphotyrosine in that it dephosphorylated the autophosphorylated EGF receptor and L-phosphotyrosine, but not a2P-Ser-casein, L-phosphoserine or L-phosphothreonine. These data suggest that the cytosolic low-Mr acid phosphatase might play a regulatory role in EGF receptor-dependent transmembrane signalling.Acid phosphatase; Epidermal growth factor receptor; Phosphotyrosine

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Section: Phosphoamino Acid Phosphatase Activitymentioning

confidence: 99%

The 18 kDa cytosolic acid phosphatase from bovine liver has phosphotyrosine phosphatase activity on the autophosphorylated epidermal growth factor receptor

et al. 1989

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“…The inhibition of TPOcatalyzed reaction as evident from present findings results in decrease in serum level of thyroid hormones. The suggested mechanism of action for enzyme inhibition may involve the conversion of thyroid peroxidase to a free radical that reacts with resorcinol moiety to produce a flavonoid radical [38] that could covalently bind to the catalytic amino acid residues on the enzyme, leading to enzyme inactivation [38]. In animal model, Boas et al [71] reported that fluorinated compounds such as perfluorooctane sulphonate and perfluorooctanoic acid also inhibited TPO activity in rats, with reductions in T4 and T3.…”

Section: Discussionmentioning

confidence: 99%

“…Thyroidal Na + -K + -ATPase activity was assayed by the modified method of Chandra et al [38]. The inorganic phosphate (Pi) liberated was determined by the method of Baginski et al [39].…”

Section: Thyroidal Na + -K + -Atpase Assaymentioning

confidence: 99%

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Tissue specific differential response in metabolic activities of cerebrum, cerebellum, pons and medulla associated with thyroid dysfunction in sub-acute fluoride toxicity

Sarkar

Pal

2015

Int Jour of Biomed Res

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Objectives: In this present in vivo study, it is intended to examine the effects of fluoride on metabolic functions of four discrete regions of rat brain associated with thyroidal insufficiency. Background: Fluoride contamination in drinking water is a major health issue. Adverse health effects of fluoride include dental and muscle fluorosis, lowering mental proficiency, neurological disorders and oxidative stress in soft tissues including brain. Thyroid is mainly concerned with regulation of metabolic homeostasis and thus supposed to be altered by fluoride toxicity. Rationale: Earlier observations indicate that fluoride toxicity imposes certain adverse effects on brain metabolic activities. Alteration in metabolic profile in brain may be affected by the thyroid gland as because this gland takes care of the overall metabolic integration of the body. Significance: The present study explores the detail mechanism of metabolic alteration of different parts of rat brain namely cerebrum, cerebellum, pons and medulla by fluoride, and also evaluates through a comparative analysis that which region is mostly affected by it. Furthermore, this study also suggests a link between brain metabolic profile and thyroid function. Methods: Male rats of Wistar strain (N=6) were orally fed with 20 mg/kg/day fluoride for 30 days. Results: Following fluoride exposure, total protein content depleted more significantly in cerebrum and medulla as compared with other brain regions. The proleolytic enzyme activity was severely affected by fluoride, especially in medulla. Changes in acidic, basic and neutral protein contents reveal that fluoride altered those parameters in a tissue specific manner. Nucleic acid contents were markedly reduced in medulla and pons by fluoride, whereas RNase activity increased in the respective brain regions. Protein carbonylation is pronounced in cerebral tissue. The neurotransmitter level was markedly reduced in cerebellum in comparison with others. Additionally, fluoride also altered thyroid metabolism as specified by depletion of nucleic acid contents and inhibition of the activities of thyroidal enzymes along with significant decrease in serum T3 and T4. Conclusion: It is suggested that fluoride altered metabolic homeostasis in cerebrum, cerebellum, pons, medulla in a tissue specific manner that might be correlated with thyroidal insufficiency.

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“…In this case ma terial precipitated by centrifugation at 1000-g for 10 min (membrane-associated frac tion) and the supernatant obtained by centrifugation at 105000 x g for 60 min (soluble fraction) were used as enzyme sources. Hydrolysis of TTP was measured by determin ing the release of inorganic phosphate by the method of Baginski et al (12). The standard reaction mixture contained: for soluble TTPase, 100 mM tris buffer (pH 9.0), 6 mM MgC12, 3 mM substrate and about 300 jug/ml of protein; for membrane-associated TTP ase, 100 mM tris-maleate buffer (pH 6.5), 3 mM MgC12, 3 mM substrate and about 600 ttg/ml of protein in a final volume of 0.5 ml.…”

Section: Methodsmentioning

confidence: 99%

Role of Thiamine Metabolism in the Central Nervous System

Iwata

Baba

Matsuda

et al. 1974

Japanese Journal of Pharmacology

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Abstract-The effects of various agents on the activity of brain thiamine triphos phatase (TTPase) in vivo and in vitro were studied. Thiamine deficiency caused a significant increase in soluble TTPase activity and a decrease in membrane-associated TTPase activity. Insulin and a fasting state did not affect these enzyme activities. DL-Methamphetamine (10 mg/kg i.p.) increased the activity of the soluble TTPase, whereas reserpine (2.5 mg/kg i.p.) caused no change in the enzyme activities. A single injection of chlopromazine (25 mg/kg s.c.) had no effect on the microsomal or soluble TTPase activities, but repeated injections reduced the activity of the micro somal enzyme. The effects of various neuroactive agents on microsomal TTPase activity were examined in vitro. Among the drugs tested, only chlorpromazine caused marked inhibition of the enzyme activity.

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Determination of phosphate: Study of labile organic phosphate interference

Cited by 391 publications

References 7 publications

The 18 kDa cytosolic acid phosphatase from bovine liver has phosphotyrosine phosphatase activity on the autophosphorylated epidermal growth factor receptor

The 18 kDa cytosolic acid phosphatase from bovine liver has phosphotyrosine phosphatase activity on the autophosphorylated epidermal growth factor receptor

Tissue specific differential response in metabolic activities of cerebrum, cerebellum, pons and medulla associated with thyroid dysfunction in sub-acute fluoride toxicity

Role of Thiamine Metabolism in the Central Nervous System

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