scholarly journals Product Formation by the Promiscuous Lanthipeptide Synthetase ProcM is under Kinetic Control

2015 ◽  
Vol 137 (15) ◽  
pp. 5140-5148 ◽  
Author(s):  
Yi Yu ◽  
Subha Mukherjee ◽  
Wilfred A. van der Donk
Keyword(s):  
Product Formation ◽  
Kinetic Control

Comparative Study of the Sol-Gel and Metallo-Organic Decomposition (MOD) Processes for the Preparation of Inorganic Materials

1992 ◽  
Vol 271 ◽  
Author(s):  
Gustavo R. Paz-Pujalt ◽  
W. Nie ◽  
C. Lurin
Keyword(s):  
Comparative Study ◽  
Chemical Reactivity ◽  
Sol Gel ◽  
Product Formation ◽  
Inorganic Materials ◽  
Kinetic Control ◽  
Reaction Thermodynamics ◽  
Points Of View ◽  
Gel Processing ◽  
Organic Decomposition

ABSTRACTSol-Gel processing and Metallo-Organic Decomposition are contrasted from the thermodynamics and chemical reactivity points of view. Differences and similarities on precursor requirements, processing characteristics, processing intermediates, and product formation pathways are outlined. Some specific examples are presented and their reaction thermodynamics are compared. Some conclusions regarding thermo-dynamic versus kinetic control are drawn from these examples.

Aspects of the mechanism of the Wittig reaction between cyclic anhydrides and stabilized phosphoranes

1982 ◽  
Vol 35 (10) ◽  
pp. 2077 ◽  
Author(s):  
AD Abell ◽  
RA Massy-Westropp
Keyword(s):  
Intermediate Product ◽  
Wittig Reaction ◽  
Product Formation ◽  
Initial Reaction ◽  
Kinetic Control ◽  
Cyclic Anhydrides ◽  
Influence Of Substituents ◽  
Phthalic Anhydrides

It has been established that the Wittig reaction between cyclic anhydrides and methoxycarbonylmethylenetriphenylphosphorane, a reaction used for the preparation of enol-lactones, proceeds via an acyclic intermediate acylated phosphorane for the three classes of anhydrides studied: succinic, maleic and phthalic. The formation of the acyclic intermediate can be irreversible or reversible, depending on the structure of the anhydride. The stereochemistry of the enol-lactones produced is not controlled by the initial reaction of the anhydride with the ylide but either during or after cyclization of the acyclic intermediate. Product formation appears to be under kinetic control with all the anhydrides studied. The influence of substituents in substituted phthalic anhydrides has been investigated.

Amidolytic Detection of Prothrombin Activation Products after SDS-Gel Electrophoresis

1989 ◽  
Vol 61 (03) ◽  
pp. 386-391 ◽  
Author(s):  
Guido Tans ◽  
Truus Janssen-Claessen ◽  
Jan Rosing
Keyword(s):  
Gel Electrophoresis ◽  
Activated Protein C ◽  
Factor Xa ◽  
Coagulation Factors ◽  
Product Formation ◽  
Chromogenic Substrate ◽  
Nitrocellulose Membrane ◽  
Activation Products ◽  
Factor Xia ◽  
Prothrombin Activation

SummaryIn this paper we report a method via which enzymatically active products formed during prothrombin activation can be detected by simple photographic means after SDS-gel electrophoresis, blotting onto a nitrocellulose membrane and visualization with the chromogenic substrate, S2238. After amidolytic detection the same nitrocellulose membrane can also be used for immunologic detection of prothrombin activation products, thus allowing a complete description of product formation during prothrombin activation.The detection limit of the so-called “amidoblot” is approximately 3 ng thrombin per gel sample which is comparable to the sensitivity of immunoblotting.It is further shown that the amidoblot technique can also be applied to other coagulation factors for which a suitable chromogenic substrate is available (factor XIIa, kallikrein, factor XIa, factor Xa, plasmin and activated protein C).

THE INFLUENCE OF ETHANOL ON THE CONVERSION OF PREGNENOLONE TO PROGESTERONE BY HUMAN PLACENTAL MICROSOMES

1974 ◽  
Vol 76 (1) ◽  
pp. 178-188 ◽  
Author(s):  
H. Lübbert ◽  
K. Pollow ◽  
R. Wagner ◽  
J. Hammerstein
Keyword(s):  
Kinetic Parameters ◽  
Enzyme Preparation ◽  
Ethanol Concentration ◽  
Hydroxysteroid Dehydrogenase ◽  
Product Formation ◽  
Linear Increase ◽  
Maximal Velocity ◽  
Microsomal Enzyme ◽  
Temperature Optima ◽  
Substrate Concentrations

ABSTRACT The effects of ethanol on kinetic parameters of placental Δ5-3β-hydroxysteroid dehydrogenase were studied. In the presence of high pregnenolone concentrations (50 μm, [S] > Km) the microsomal enzyme preparation exhibited an almost linear increase in activity as the ethanol concentration in the medium was raised from 2.5 to 15 % (v/v). At lower substrate concentrations ([S] << Km) ethanol caused inhibition. Other effects of ethanol were: linearity of product formation with time was prolonged; the maximal velocity was markedly increased; the Km for pregnenolone slightly decreased with increasing ethanol concentrations (2.5 to 10 %, v/v) whereas the Km for NAD remained the same. The pH and temperature optima of the reaction were unaffected by ethanol. Other organic solvents caused similar effects.

Sign in / Sign up

Export Citation Format

Share Document