Confirmation of the structure of nisin and its major degradation product by FAB-MS and FAB-MS/MS

1988 ◽  
Vol 44 (3) ◽  
pp. 266-270 ◽  
Author(s):  
M. Barber ◽  
G. J. Elliot ◽  
R. S. Bordoli ◽  
B. N. Green ◽  
B. W. Bycroft
Keyword(s):  
Degradation Product ◽  
Major Degradation Product

Glyphosate Residues in Soil and Air: An Integrated Review

2020 ◽  
Author(s):  
Evagelia Tzanetou ◽  
Helen Karasali
Keyword(s):  
Degradation Product ◽  
Critical Review ◽  
Safety Evaluation ◽  
Environmental Safety ◽  
Soil Ecosystem ◽  
Aminomethylphosphonic Acid ◽  
The Relationship ◽  
Surface And Groundwater ◽  
Major Degradation Product

Glyphosate [N-(phosphonomethyl) glycine] (GPS) is currently the most commonly applied herbicide worldwide. Given the widespread use of glyphosate, the investigation of the relationship between glyphosate and soil ecosystem is critical and has great significance for its valid application and environmental safety evaluation. However, although the occurrence of glyphosate residues in surface and groundwater is rather well documented, only few information are available for soils and even fewer for air. Due to this, the importance of developing methods that are effective and fast to determine and quantify glyphosate and its major degradation product, aminomethylphosphonic acid (AMPA), is emphasized. Based on its structure, the determination of this pesticide using a simple analytical method remains a challenge, a fact known as the “glyphosate paradox.” In this chapter a critical review of the existing literature and data comparison studies regarding the occurrence and the development of analytical methods for the determination of pesticide glyphosate in soil and air is performed.

Kinetic Degradation Study of Dapagliflozin Coupled with UHPLC Separation in the Presence of Major Degradation Product and Metformin

2019 ◽  
Vol 82 (4) ◽  
pp. 777-789 ◽  
Author(s):  
Wafaa A. Zaghary ◽  
Shereen Mowaka ◽  
Moataz S. Hendy
Keyword(s):  
Degradation Product ◽  
Degradation Study ◽  
Major Degradation Product

scholarly journals Deciphering the chemical instability of sphaeropsidin A under physiological conditions – degradation studies and structural elucidation of the major metabolite

2020 ◽  
Vol 18 (40) ◽  
pp. 8147-8160
Author(s):  
Alet E. van der Westhuyzen ◽  
Aude Ingels ◽  
Rémi Rosière ◽  
Karim Amighi ◽  
Lukas Oberer ◽  
...  
Keyword(s):  
Degradation Product ◽  
Structural Elucidation ◽  
Major Metabolite ◽  
Fungal Metabolite ◽  
Physiological Conditions ◽  
Chemical Instability ◽  
Degradation Studies ◽  
Major Degradation Product ◽  
Sphaeropsidin A

The degradation of the fungal metabolite sphaeropsidin A, under physiological conditions, was investigated and the structure of the major degradation product determined.

Like Fibrin, (DD)E, the Major Degradation Product of Crosslinked Fibrin, Protects Plasmin from Inhibition by α2-antiplasmin

2001 ◽  
Vol 85 (03) ◽  
pp. 502-508 ◽  
Author(s):  
Agnes Lee ◽  
James Fredenburgh ◽  
Ronald Stewart ◽  
Janice Rischke ◽  
Jeffrey Weitz
Keyword(s):  
Protective Effect ◽  
Plasminogen Activator ◽  
Degradation Product ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Tissue Type Plasminogen Activator ◽  
Potent Stimulator ◽  
Type Plasminogen Activator ◽  
Kd Values ◽  
Major Degradation Product

SummaryPlasmin generation is localized to the fibrin surface because tissue-type plasminogen activator (t-PA) and plasminogen bind to fibrin, an interaction that stimulates plasminogen activation over a hundred-fold. To ensure efficient fibrinolysis, plasmin bound to fibrin is protected from inhibition by α2-antiplasmin. (DD)E, a major soluble degradation product of cross-linked fibrin that is a potent stimulator of t-PA, compromises the fibrin-specificity of t-PA by promoting systemic activation of plasminogen. In this study we investigated whether (DD)E also protects plasmin from inhibition by α2-antiplasmin, facilitating degradation of this soluble t-PA effector. (DD)E and fibrin reduce the rate of plasmin inhibition by α2-antiplasmin by 5- and 10-fold, respectively. Kringle-dependent binding of plasmin to (DD)E and fibrin, with Kd values of 52 and 410 nM, respectively, contributes to the protective effect. When (DD)E is extensively degraded by plasmin, yielding uncomplexed fragment E and (DD), protection of plasmin from inhibition by α2-antiplasmin is attenuated. These studies indicate that (DD)E-bound plasmin, whose generation reflects the ability of (DD)E to stimulate plasminogen activation by t-PA, has the capacity to degrade (DD)E by virtue of its resistance to inhibition. This provides a mechanism to limit the concentration of (DD)E and maintain the fibrin-specificity of t-PA.

scholarly journals Stability of Cephalosporin Prodrug Esters in Human Intestinal Juice: Implications for Oral Bioavailability

1998 ◽  
Vol 42 (10) ◽  
pp. 2602-2606 ◽  
Author(s):  
Klaus Stoeckel ◽  
Werner Hofheinz ◽  
Jean Paul Laneury ◽  
Patrick Duchene ◽  
Steve Shedlofsky ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Degradation Product ◽  
Phosphate Buffer ◽  
Degradation Products ◽  
Cefuroxime Axetil ◽  
Intestinal Fluid ◽  
Intestinal Juice ◽  
Time Courses ◽  
High Degree ◽  
Major Degradation Product

ABSTRACT The levels of degradation of cefetamet pivoxil (CAT), cefuroxime axetil (CAE), and cefpodoxime proxetil (CPD) in 0.6 M phosphate buffer (pH 7.4) and human intestinal juice (pH 7.4) at 37°C over 24 h were compared. Significant differences in the time courses of degradation and in the patterns of degradation products were observed. (i) The relative proportions of the Δ2- and Δ3-cephalosporins were roughly reversed in the two incubation media. In phosphate buffer, the major degradation product was the Δ2-cephalosporin (CAT = 61%; CAE = 74%; CPD = 85%), while in intestinal juice it was the Δ3-cephalosporin (CAT = 86%; CAE = 75%; CPD = 87%). (ii) Generally, the degradation of the prodrug esters progressed faster in intestinal juice than in phosphate buffer (e.g., for CAT the half-lives [t 1/2s] were 0.78 and 4.3 h, respectively). (iii) The two diastereoisomers of CAE and CPD were degraded at different rates in intestinal juice (for the CAE diasteroisomers, t 1/2s = 0.37 and 0.93 h; for the CPD diastereoisomers,t 1/2s = 0.18 and 0.98 h) but were degraded at similar rates in phosphate buffer (for the CAE diastereoisomers, t 1/2 = 1.6 h; for the CPD t 1/2 diastereoisomers, = 2.2 h). It is concluded that (i) the Δ2 isomerization does not significantly affect the bioavailability of prodrug esters since enzymatic hydrolysis in the intestinal fluid proceeds mainly to the active Δ3-cephalosporin and (ii) the high degree of stereoselectivity of the enzymatic ester hydrolysis should make it possible to increase the bioavailabilities of certain prodrug esters (CAE, CPD) by using the more stable diasterioisomer.

Binding and degradation studies on angiotensin II

1984 ◽  
Vol 62 (9) ◽  
pp. 1203-1208 ◽  
Author(s):  
A. K. Grover ◽  
C. Y. Kwan ◽  
P. Kostka ◽  
S. M. Shephard ◽  
E. E. Daniel
Keyword(s):  
Angiotensin Ii ◽  
Protease Inhibitors ◽  
Degradation Product ◽  
Binding Sites ◽  
Mesenteric Artery ◽  
Specific Binding ◽  
Parent Compound ◽  
Rat Mesenteric Artery ◽  
Major Degradation Product ◽  
Membrane Concentration

125I-labelled angiotensin II (AII) and [3H]AII showed specific binding to rat mesenteric artery microsomes. The binding in either instance was inhibited by the AII analog saralasin. [3H]AII was not degraded by the microsomes but 125I-labelled AII was degraded. Autoradiography of thin layer chromatograms of 125I-labelled AII treated with microsomes showed the parent peak (Rf = 0.4–0.45) and a single major degradation product peak (Rf = 0.25–0.30), and [125I]NaI had an Rf value higher than both 125I-labelled AII and its degradation product. Chromatography of unlabelled AII or [3H]AII gave the same Rf value as 125I-labelled AII, but unlabelled AIII moved with Rf = 0.55–0.60. The formation of the degradation product was time and membrane concentration dependent. The degradation occurred at pH 6 and 7 but not at pH 8. However, specific binding of 125I-label1ed AII was also lower at pH 8. The degradation could not be completely inhibited by the use of crude particulate fractions instead of microsomes, by preparing membranes in presence of protease inhibitors, or by including protease inhibitors and sulfhydryl agents in the assay medium. However, the degradation product neither showed specific binding to the microsomes nor interfered with the specific binding of 125I-labelled AII. Furthermore, the tightly bound material eluted from the microsomes in presence of 0.05 M acetic acid at 0 °C consisted predominantly of the parent compound. The implications of these findings are discussed both in terms of validity of the binding experiments and possible relationship between the degradation and the receptor binding sites in the membrane.

HPLC–DAD Method for Simultaneous Determination of Dipyrone (Metamizole) and Caffeine in Tablets and Identification of Major Degradation Product by Direct Infusion ESI–MS

2017 ◽  
Vol 80 (3) ◽  
pp. 489-495 ◽  
Author(s):  
James Cabral Vieira ◽  
Rubia Adriele Sversut ◽  
Isadora Theodoro Maciel ◽  
Aline Regina Hellmann Carollo ◽  
Marcos Serrou do Amaral ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Degradation Product ◽  
Direct Infusion ◽  
Esi Ms ◽  
Major Degradation Product

Identification of 7α-,12α-dihydroxy-3-oxo cholanoic acid as the major degradation product from cholic by C. perfringens

1978 ◽  
Vol 9 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Ian A. Macdonald ◽  
Thomas P. Forrest ◽  
Gary A. Costain ◽  
Barbara G. Rao
Keyword(s):  
Degradation Product ◽  
Cholanoic Acid ◽  
Major Degradation Product
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