scholarly journals Adenosine 5′-tetraphosphate phosphohydrolase from yellow lupin seeds: purification to homogeneity and some properties

1997 ◽  
Vol 328 (1) ◽  
pp. 257-262 ◽  
Author(s):  
Andrzej GURANOWSKI ◽  
Elżbieta STARZYŃSKA ◽  
Paul BROWN ◽  
G. Michael BLACKBURN
Keyword(s):  
Divalent Cation ◽  
Polypeptide Chain ◽  
Lupinus Luteus ◽  
Nucleoside Triphosphate ◽  
Yellow Lupin ◽  
Ph Optimum ◽  
Single Polypeptide Chain ◽  
Lupin Seeds ◽  
Single Polypeptide ◽  
Hydrolysis Of

Adenosine 5ʹ-tetraphosphate phosphohydrolase (EC 3.6.1.14) has been purified to homogeneity from the meal of yellow lupin (Lupinus luteus) seeds. The enzyme is a single polypeptide chain of 25±1 kDa. It catalyses the hydrolysis of a nucleoside 5ʹ-tetraphosphate to a nucleoside triphosphate and orthophosphate, and hydrolysis of tripolyphosphate but neither pyrophosphate nor tetraphosphate. A divalent cation, Mg2+, Co2+, Ni2+ or Mn2+, is required for these reactions. The pH optimum for hydrolysis of adenosine 5ʹ-tetraphosphate (p4A) is 8.2, Vmax is 21±1.7 μmol/min per mg of protein and the Km for p4A is 3±0.6 μM. At saturating p4A concentrations, the rate constant for the reaction is 8.5±0.7 s-1 [at 30 °C, in 50 mM Hepes/KOH (pH 8.2)/5 mM MgCl2/0.1 mM dithiothreitol]. p4A and guanosine 5ʹ-tetraphosphate are hydrolysed at the same rate. Adenosine 5ʹ-pentaphosphate (p5A) is degraded 1/200 as fast and is converted into ATP and two molecules of orthophosphate, which are liberated sequentially. This contrasts with the cleavage of p5A by the lupin diadenosine tetraphosphate hydrolase (EC 3.6.1.17), which gives ATP and pyrophosphate. Zn2+, F- and Ca2+ ions inhibit the hydrolysis of p4A with I50 values of 0.1, 0.12 and 0.2 mM respectively.

scholarly journals Modeling studies of potato nucleoside triphosphate diphosphohydrolase NTPDase1: an insight into the catalytic mechanism.

2008 ◽  
Vol 55 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Anna Kozakiewicz ◽  
Piotr Neumann ◽  
Mariusz Banach ◽  
Michał Komoszyński ◽  
Andrzej Wojtczak
Keyword(s):  
Catalytic Mechanism ◽  
Polypeptide Chain ◽  
Hydrolytic Activity ◽  
Nucleoside Triphosphate ◽  
Nucleoside Triphosphate Diphosphohydrolase ◽  
Single Polypeptide Chain ◽  
Mechanism Of Hydrolysis ◽  
Single Polypeptide ◽  
Actin Superfamily ◽  
Insight Into

Nucleoside triphosphate diphosphohydrolase--NTPDase1 (apyrase, EC 3.6.1.5) was modeled based on sequence homology. The single polypeptide chain of apyrase is folded into two domains. The putative catalytic site with the apyrase conserved regions (ACR 1-5) is located between these two domains. Modeling confirmed that apyrase belongs to the actin superfamily of proteins. The amino acids interacting with the nucleoside triphosphate substrate and probably involved in the catalyzed hydrolysis were identified. The proposed two-step catalytic mechanism of hydrolysis involves Thr127 and Thr55 as potential nucleophilic factors responsible for the cleavage of the Pgamma and Pbeta anhydride bonds, respectively. Their action seems to be assisted by Glu170 and Glu78 residues, respectively. The presence of two nucleophiles in the active site of apyrase explains the differences in the hydrolytic activity between apyrases and other enzymes belonging to the NTPDase family.

Debranching enzyme from rabbit skeletal muscle; Evidence for the location of two active centres on a single polypeptide chain

FEBS Letters ◽  
1975 ◽  
Vol 58 (1-2) ◽  
pp. 181-185 ◽  
Author(s):  
Edna J. Bates ◽  
Gillian M. Heaton ◽  
Carol Taylor ◽  
John C. Kernohan ◽  
Philip Cohen
Keyword(s):  
Skeletal Muscle ◽  
Polypeptide Chain ◽  
Rabbit Skeletal Muscle ◽  
Debranching Enzyme ◽  
Single Polypeptide Chain ◽  
Single Polypeptide ◽  
Active Centres

scholarly journals Hepatic microsomal epoxide hydrase. Chemical evidence for a single polypeptide chain.

1979 ◽  
Vol 254 (14) ◽  
pp. 6240-6243 ◽  
Author(s):  
G C DuBois ◽  
E Appella ◽  
R Armstrong ◽  
W Levin ◽  
A Y Lu ◽  
...  
Keyword(s):  
Polypeptide Chain ◽  
Single Polypeptide Chain ◽  
Single Polypeptide ◽  
Chemical Evidence

scholarly journals Identification of Igh-C-linked determinants on suppressor T cell hybrids and factors specific for L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT).

1985 ◽  
Vol 162 (3) ◽  
pp. 1044-1059 ◽  
Author(s):  
C M Sorensen ◽  
R J Hayashi ◽  
C W Pierce
Keyword(s):  
T Cells ◽  
T Cell ◽  
Polypeptide Chain ◽  
Spleen Cells ◽  
Suppressor T Cell ◽  
Cell Hybrids ◽  
Single Polypeptide Chain ◽  
Functional Classes ◽  
Single Polypeptide ◽  
Ig Allotype

Hyperimmunization of BALB/c mice with concanavalin A-stimulated blasts from the Ig allotype-congenic strain, C.B20, results in the production of antibodies reactive with T cells in an allotype-restricted manner. Spleen cells from these hyperimmune BALB/c mice were used to generate a panel of hybridomas that secrete monoclonal antibodies, reactive, in an allotype-restricted manner, exclusively with T cells subpopulations, and in particular, reactive with suppressor T cell hybridomas and their secreted soluble factors. Two functional classes of antibodies were identified: those that react with single polypeptide-chain suppressor T cell factors (TsF1) and the suppressor T cell hybridomas that produce such factors, and those that react with two polypeptide-chain suppressor T cell factors (TsF2) and their corresponding suppressor T cell hybridomas. These two classes of antibody were used to isolate molecules from the membranes of the respective suppressor T cell hybrids that are functionally and structurally related to the secreted suppressor T cell factors, suggesting a receptor function for these molecules.

The power of the force: mechano-physiology of the giant titin

2018 ◽  
Vol 2 (5) ◽  
pp. 681-686 ◽  
Author(s):  
Jaime Andrés Rivas-Pardo
Keyword(s):  
Amino Acid ◽  
Human Body ◽  
Actin Filaments ◽  
Polypeptide Chain ◽  
Single Gene ◽  
The Other ◽  
Amino Acid Residues ◽  
The Third ◽  
Single Polypeptide Chain ◽  
Single Polypeptide

Titin — the largest protein in the human body — spans half of the muscle sarcomere from the Z-disk to the M-band through a single polypeptide chain. More than 30 000 amino acid residues coded from a single gene (TTN, in humans Q8WZ42) form a long filamentous protein organized in individual globular domains concatenated in tandem. Owing to its location and close interaction with the other muscle filaments, titin is considered the third filament of muscle, after the thick-myosin and the thin-actin filaments.

scholarly journals The purification and some properties of rusticyanin, a blue copper protein involved in iron(II) oxidation from Thiobacillus ferro-oxidans

1978 ◽  
Vol 174 (2) ◽  
pp. 497-502 ◽  
Author(s):  
J C Cox ◽  
D H Boxer
Keyword(s):  
Polypeptide Chain ◽  
Iron Oxidation ◽  
Exchange Chromatography ◽  
Blue Copper Protein ◽  
Blue Copper ◽  
Copper Protein ◽  
Optical Absorbance ◽  
Single Polypeptide Chain ◽  
Arginine Residues ◽  
Single Polypeptide

The ‘blue’ copper-containing protein rusticyanin was purified to homogeneity from cells of the chemolithotrophic bacterium Thiobacillus ferro-oxidans by (NH4)SO4 fractionation and ion-exchange chromatography. The protein, which is stable at low pH, consists of a single polypeptide chain of mol. wt. 16500 and possesses 0.79 (+/- 0.28)g-atom of Cu/mol. The protein, which does not contain arginine residues, has optical absorbance maxima at 287, 450, 597 and 750 nm and is generally similar to azurin. The isolated protein is reduced directly by Fe2+ with a 1:1 stoicheiometry to Cu. On reduction by Fe2+ the absorption peaks at 450, 597 and 750 nm are abolished, with the appearance of a new absorption band at 320 nm. The results obtained are consistent with rusticyanin being the initial acceptor of electrons from Fe2+ during respiratory iron oxidation.

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