Cathepsin B2 measurement by sensitive fluorometric ammonia analysis

Taylor, Steve L.; Ninjoor, V.; Dowd, D.M.; Tappel, Al L.

doi:10.1016/0003-2697(74)90140-7

Cited by 102 publications

(71 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For all gas analyses 100 ml gas samples were injected with a glass syringe. Ammonium concentrations were measured using the o-phthaldialdehyde (OPA) method (Taylor et al 1974). …”

Section: Methodsmentioning

confidence: 99%

Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

et al. 2010

View full text Add to dashboard Cite

The ability to utilize atmospheric nitrogen (N2) as a sole nitrogen source is an important trait for prokaryotes. Knowledge of N2 fixation by methanotrophs is needed to understand their role in nitrogen cycling in different environments. The verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ strain SolV was investigated for its ability to fix N2. Physiological studies were combined with nitrogenase activity measurements and phylogenetic analysis of the nifDHK genes, encoding the subunits of the nitrogenase. ‘M. fumariolicum’ SolV was able to fix N2 at low oxygen (O2) concentration (0.5 %, v/v) in chemostat cultures. This low oxygen concentration was also required for an optimal nitrogenase activity [47.4 nmol ethylene h−1 (mg cell dry weight)−1]. Based on acetylene reduction assay and growth experiments, the nitrogenase of strain SolV seems to be extremely oxygen sensitive compared to most proteobacterial methanotrophs. The activity of the nitrogenase was not inhibited by ammonium concentrations up to 94 mM. This is believed to be the first report on the physiology of N2 fixation within the phylum Verrucomicrobia.

show abstract

“…For all gas analyses 100 ml gas samples were injected with a glass syringe. Ammonium concentrations were measured using the o-phthaldialdehyde (OPA) method (Taylor et al 1974). …”

Section: Methodsmentioning

confidence: 99%

Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The potential amidase activity of cathepsin B was evaluated using a sensitive fluorimetric assay for ammonia based on the reaction between o-phthaldialdehyde and β-mercaptoethanol [22]. An ammonia standard curve was generated using ammonium sulphate (0-0.27 µM) in 0.2 M sodium phosphate, pH 7.4, containing 3.72 mM o-phthaldialdehyde, 3.56 mM β-mercaptoethanol and 0.24 µM Abz-FRF(4NO # )F-NH # to reproduce as closely as possible the conditions in the mixture to be assayed.…”

Section: Detection Of Potential Amidase Activitymentioning

confidence: 99%

S′2 substrate specificity and the role of His110 and His111 in the exopeptidase activity of human cathepsin B

Krupa

Hasnain

Nägler

et al. 2002

Biochemical Journal

View full text Add to dashboard Cite

The ability of the lysosomal cysteine protease cathepsin B to function as a peptidyldipeptidase (removing C-terminal dipeptides) has been attributed to the presence of two histidine residues (His110 and His111) present in the occluding loop, an extra peptide segment located in the primed side of the active-site cleft. Whereas His111 is unpaired, His110 is present as an ion pair with Asp22 on the main body of the protease. This ion pair appears to act as a latch to hold the loop in a closed position. The exopeptidase activity of cathepsin B, examined using quenched fluorescence substrates, was shown to have a 20-fold preference for aromatic side chains in the P′3 position relative to glutamic acid as the least favourable residue. Site-directed mutagenesis demonstrated that His111 makes a positive 10-fold contribution to the exopeptidase activity, whereas His110 is critical for this action with the Asp22—His110 ion pair stabilizing the electrostatic interaction by a maximum of 13.9kJ/mol (3.3kcal/mol). These studies showed that cathepsin B is optimized to act as an exopeptidase, cleaving dipeptides from protein substrates in a successive manner, because of its relaxed specificity in P′3 and its other subsites.

show abstract

“…The ammonia formed was measured according to fluorimetric assay, proposed by Taylor et al [12] . Substrate concentrations in the MAO inhibition assay were 1 mmol/l serotonine (type A), 0.1 mmol/l betaphenylethylamine (type B), 1 mmol/l tyrosine (type A+B).…”

Section: Biochemical Evaluations Evaluation Of the Degree Of Mao Inhimentioning

confidence: 99%

Synthesis, Toxicological, and Pharmacological Assessment of Derivatives of 2-Aryl-4-(3-arylpropyl)morpholines

Avramova¹,

Danchev

Buyukliev³

et al. 1998

Arch. Pharm. Pharm. Med. Chem.

View full text Add to dashboard Cite

The synthesis of nine original morpholine derivatives, i.e. 2‐aryl‐4‐(3‐arylpropyl)morpholines, is described. The structure of all synthesised derivatives was proved by IR and 1H‐NMR, and some of them by 13C‐NMR. Acute toxicity studies of the compounds were performed on mice. A comparative pharmacological study of the in vivo effects on the central nervous system was undertaken using the screening tests: hexobarbital induced sleeping time; locomotor activity; and behaviour despair (for antidepressive activity). The most active compound 4‐(2‐benzoylethyl)‐2‐phenyl‐3‐methyl) morpholine 4e was studied for MAO‐A and MAO‐B inhibition in vitro in rat brain mitochondria preparations.

show abstract

Cathepsin B2 measurement by sensitive fluorometric ammonia analysis

Cited by 102 publications

References 18 publications

Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

S′2 substrate specificity and the role of His110 and His111 in the exopeptidase activity of human cathepsin B

Synthesis, Toxicological, and Pharmacological Assessment of Derivatives of 2-Aryl-4-(3-arylpropyl)morpholines

Contact Info

Product

Resources

About