scholarly journals Hint2, the mitochondrial nucleoside 5'-phosphoramidate hydrolase; properties of the homogeneous protein from sheep (Ovis aries) liver.

2013 ◽  
Vol 60 (2) ◽  
Author(s):  
Ewa Bretes ◽  
Anna M Wojdyła-Mamoń ◽  
Joanna Kowalska ◽  
Jacek Jemielity ◽  
Renata Kaczmarek ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Simple Procedure ◽  
Mitochondrial Fraction ◽  
Protein Family ◽  
Ovis Aries ◽  
Molecular Properties ◽  
Kinetic Properties ◽  
Biological Functions ◽  
Sheep Liver ◽  
Hydrolysis Of

Adenosine 5'-phosphoramidate (NH2-pA) is a rare natural nucleotide and its biochemistry and biological functions are poorly recognized. All organisms have proteins that may be involved in the catabolism of NH2-pA. They are members of the HIT protein family and catalyze hydrolytic splitting of NH2-pA to 5'-AMP and ammonia. At least five HIT proteins have been identified in mammals; however, the enzymatic and molecular properties of only Fhit and Hint1 have been comprehensively studied. Our study focuses on the Hint2 protein purified by a simple procedure to homogeneity from sheep liver mitochondrial fraction (OaHint2). Hint1 protein was also prepared from sheep liver (OaHint1) and the molecular and kinetic properties of the two proteins compared. Both function as homodimers and behave as nucleoside 5'-phosphoramidate hydrolases. The molecular mass of the OaHint2 monomer is 16 kDa and that of the OaHint1 monomer 14.9 kDa. Among potential substrates studied, NH2-pA appeared to be the best; the Km and kcat values estimated for this compound are 6.6 μM and 68.3 s⁻¹, and 1.5 μM and 11.0 s⁻¹ per natively functioning dimer of OaHint2 and OaHint1, respectively. Studies of the rates of hydrolysis of different NH2-pA derivatives show that Hint2 is more specific towards compounds with a P-N bond than Hint1. The thermostability of these two proteins is also compared.

scholarly journals Deacylation of acetyl-coenzyme A and acetylcarnitine by liver preparations

1978 ◽  
Vol 171 (2) ◽  
pp. 299-303 ◽  
Author(s):  
A M Snoswell ◽  
P K Tubbs
Keyword(s):  
Gel Filtration ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Carnitine Acetyltransferase ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Sheep Liver ◽  
Chain Acyl ◽  
Coa Hydrolase ◽  
Hydrolysis Of

The breakdown of acetylcarnitine catalysed by extracts of rat and sheep liver was completely abolished by Sephadex G-25 gel filtration, whereas the hydrolysis of acetyl-CoA was unaffected. Acetyl-CoA and CoA acted catalytically in restoring the ability of Sephadex-treated extracts to break down acetylcarnitine, which was therefore not due to an acetylcarnitine hydrolase but to the sequential action of carnitine acetyltransferase and acetyl-CoA hydrolase. Some 75% of the acetyl-CoA hydrolase activity of sheep liver was localized in the mitochondrial fraction. Two distinct acetyl-CoA hydrolases were partially purified from extracts of sheep liver mitochondria. Both enzymes hydrolysed other short-chain acyl-CoA compounds and succinyl-CoA (3-carboxypropionyl-CoA), but with one acetyl-CoA was the preferred substrate.

scholarly journals Competition for minerals (Zn, Mn, Fe, Cu) and Cd between sheep tapeworm (Moniezia expansa) and its definitive host sheep (Ovis aries)

2011 ◽  
Vol 48 (4) ◽  
pp. 237-243 ◽  
Author(s):  
I. Jankovská ◽  
D. Lukešová ◽  
J. Száková ◽  
I. Langrová ◽  
J. Vadlejch ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Ovis Aries ◽  
Emission Spectrometry ◽  
Control Group ◽  
Inductively Coupled ◽  
Sheep Liver ◽  
Moniezia Expansa ◽  
Cd Exposure ◽  
Sheep Muscle

AbstractConcentrations of various essential and toxic elements (Zn, Mn, Fe, Cu and Cd) were analysed by inductively coupled plasma optical emission spectrometry (ICP-OES) in the sheep tapeworm (Moniezia expansa) and in different tissues of its host Ovis aries. The element concentrations of the cestode parasites were compared to different organs (liver, kidney, and muscle) of sheep that were exposed to experimental amounts of Cd (0.2 g of CdCl2 added to 10 ml of distilled water and administered orally to the sheep every day for a period of 1 week). All sheep were randomly divided into four groups; the first group (Cd) contained uninfected, Cd exposed sheep, and its control (group C) were uninfected and unexposed to Cd; the second group (TCd) contained infected, Cd exposed sheep, and its control (group CT) contained infected, unexposed sheep. The experimental Cd exposure resulted in significantly higher Mn concentrations in sheep tapeworms (10.0 mg/kg) than in sheep muscle (0.6 mg/kg) and kidney (0.8 mg/kg). The experimental Cd exposure also significantly decreased the Cu concentrations in sheep liver and muscle. Moreover Cd exposure decreased the Fe concentrations in sheep kidney but caused it to increase in sheep liver and muscle. Zinc concentrations showed no differences between groups (Cd, TCd, C, T) in any monitored sheep tissues. The article also discuss the effect of tapeworm infection on a significant decrease of Fe in sheep muscle, liver and kidneys, as well as a decrease in Cu levels of the muscles and liver. This mineral imbalance may contribute to various health problems such as osteoporosis, metabolic processes disorder, antioxidant (SOD) dysfunction etc.

Enzymatic Hydrolysis of PET: Structural Diversity and Kinetic Properties of Cutinases from Thermobifida

2014 ◽  
Vol 31 ◽  
pp. S88
Author(s):  
Altijana Hromic ◽  
Doris Ribitsch ◽  
Andrzej Lyskowski ◽  
Georg Steinkellner ◽  
Helmut Schwab ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Structural Diversity ◽  
Kinetic Properties ◽  
Hydrolysis Of

A simple procedure using trinitrobenzenesulphonic acid for monitoring proteolysis in cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 585-596 ◽  
Author(s):  
Anna Polychroniadou
Keyword(s):  
Simple Procedure ◽  
Water Soluble ◽  
Acid Solutions ◽  
Amino Groups ◽  
Total N ◽  
Cheese Ripening ◽  
Amino Acid Solutions ◽  
Hydrolysis Of ◽  
Good Agreement

SummaryA simple, rapid and sensitive spectrophotometric assay was developed and evaluated for monitoring proteolysis during cheese ripening, based on the fact that α-amino groups released by hydrolysis of cheese proteins react with trinitrobenzenesulphonic acid to form products that absorb strongly at 420 nm. A linear relationship was shown to exist between A420 and concentration of free α amino groups up to 0·5 HIM (r = 0·999, 38 df, P < 0·001). Repeatability of the method was satisfactory. The coefficient of variance was 0·53% for amino acid solutions and 1·19% for cheese extracts. Average recovery of glycine added to the cheese was 104 ± 2·9%. A comparison of the above method with that of determination of water-soluble N to total N ratio showed that there was good agreement between these two methods of assessment of proteolysis in cheese (r = 0·857, 32 df, P < 0·001). Mainly Feta and Teleme cheese were examined, but a similar correlation was obtained with hard Greek cheeses. Analytical conditions of the procedure are discussed.

scholarly journals Studies on the mechanism of sheep liver cytosolic aldehyde dehydrogenase

1985 ◽  
Vol 225 (1) ◽  
pp. 159-165 ◽  
Author(s):  
F M Dickinson
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Kinetic Studies ◽  
Dissociation Reaction ◽  
Quenching Effect ◽  
Sheep Liver ◽  
Association Reaction ◽  
Hydrolysis Of

The dissociation of the aldehyde dehydrogenase X NADH complex was studied by displacement with NAD+. The association reaction of enzyme and NADH was also studied. These processes are biphasic, as shown by McGibbon, Buckley & Blackwell [(1977) Biochem. J. 165, 455-462], but the details of the dissociation reaction are significantly different from those given by those authors. Spectral and kinetic experiments provide evidence for the formation of abortive complexes of the type enzyme X NADH X aldehyde. Kinetic studies at different wavelengths with transcinnamaldehyde as substrate provide evidence for the formation of an enzyme X NADH X cinnamoyl complex. Hydrolysis of the thioester relieves a severe quenching effect on the fluorescence of enzyme-bound NADH.

scholarly journals Peptidase activity of β-lactamases

1999 ◽  
Vol 341 (2) ◽  
pp. 409-413 ◽  
Author(s):  
Noureddine RHAZI ◽  
Moreno GALLENI ◽  
Michael I. PAGE ◽  
Jean-Marie FRÈRE
Keyword(s):  
Molecular Mass ◽  
Enterobacter Cloacae ◽  
Peptidase Activity ◽  
Rate Enhancement ◽  
Enhancement Factors ◽  
Lactam Ring ◽  
Class C ◽  
Hydrolysis Of

Although β-lactamases have generally been considered as being devoid of peptidase activity, a low but significant hydrolysis of various N-acylated dipeptides was observed with representatives of each class of β-lactamases. The kcat/Km values were below 0.1 M-1˙s-1, but the enzyme rate enhancement factors were in the range 5000-20000 for the best substrates. Not unexpectedly, the best ‘peptidase’ was the class C β-lactamase of Enterobacter cloacae P99, but, more surprisingly, the activity was always higher with the phenylacetyl- and benzoyl-D-Ala-D-Ala dipeptides than with the diacetyl- and α-acetyl-L-Lys-D-Ala-D-Ala tripeptides, which are the preferred substrates of the low-molecular-mass, soluble DD-peptidases. A comparison between the β-lactamases and DD-peptidases showed that it might be as difficult for a DD-peptidase to open the β-lactam ring as it is for the β-lactamases to hydrolyse the peptides, an observation which can be explained by geometric and stereoelectronic considerations.

Purification and characterization of a lectin from Xanthomonas campestris NCIM 5028

1996 ◽  
Vol 42 (6) ◽  
pp. 609-612 ◽  
Author(s):  
Bhagyashree Joshi ◽  
Jayant M. Khire ◽  
Hephzibah SivaRaman ◽  
M. Islam Khan
Keyword(s):  
Molecular Mass ◽  
Host Plant ◽  
Xanthomonas Campestris ◽  
Simple Procedure ◽  
Gel Filtration ◽  
Purification And Characterization ◽  
Ammonium Sulphate Precipitation ◽  
Molecular Masses ◽  
Lectin Purification

A lectin was isolated from culture filtrates of Xanthomonas campestris NCIM 5028, by a simple procedure of hydrophobic chromatography on phenyl-Sepharose after ammonium sulphate precipitation. The lectin was a heterodimer, with subunit molecular masses of 30 000 and 28 000. Gel filtration on S-300 column, calibrated with markers, showed its molecular mass to be approximately 70 000. Its isoelectric point was 7.2. The agglutination of the rabbit erythrocytes by the lectin was inhibited by fetuin glycopeptides and host plant (Brassica oleracea) extracts.Key words: Xanthomonas campestris, lectin, purification.

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