scholarly journals Reactions of I,I-Diacetoxyiodobenzene with Proteins: Conversion of Amide Side-Chains to Amines

1981 ◽  
Vol 34 (4) ◽  
pp. 395 ◽  
Author(s):  
Leo A Holt ◽  
Brian Milligan
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Side Reactions ◽  
Side Chains ◽  
Diaminobutyric Acid ◽  
Methyl Cyanide ◽  
Diaminopropionic Acid ◽  
Derivatives Of

Experiments with the N-benzyloxycarbonyl derivatives of asparagine and glutamine as models show that, in unbuffered solutions, I,I-diacetoxyiodobenzene (1) is more effective than the corresponding trifluoroacetoxy derivative (2) for converting the amide side-chains of proteins to amines. Maximum modification of the glutamine residues of insulin and lysozyme occurs within 1-2 h of treatment with 1 in aqueous methyl cyanide at 20�C, but asparagine residues react more slowly. The amide side-chains are converted to the corresponding amines in at least 90 % yield, as shown by analysis of acid hydrolysates for aspartic acid, lX,p-diaminopropionic acid, glutamic acid and lX,y-diaminobutyric acid. Numerous side-reactions also occur, tyrosine, cystine, methionine, arginine, lysine and N-terminal residues all being modified to some extent.

scholarly journals The protective action of some amino-acids against the effect of heat on complement

1953 ◽  
Vol 51 (1) ◽  
pp. 140-144 ◽  
Author(s):  
J. Gordon
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Guinea Pig ◽  
Protective Effect ◽  
Glutamic Acid ◽  
High Molecular Weight ◽  
Aspartic Acid ◽  
Protective Action ◽  
Derivatives Of ◽  
Pig Serum

1. Glycine, alanine, and several isomers of alanine, DL-glutamic acid and DL-aspartic acid, when added to fresh guinea-pig serum and allowed to stand on the bench for half an hour, will protect the complement of this serum from destruction by heating at 55 and 56° C. for half an hour, but most of the complement activity is destroyed by heating at 57° C. and it is completely destroyed at 58° C. after half an hour.2. Derivatives of glycine do not have any protective effect.3. Various substances of high molecular weight, that might be described as ‘protective colloids’ do not have any protective effect.4. How these amino-acids when added to serum alter the heat-lability of the complement is not understood.

Neuronal depressant effects of diethylester derivatives of excitatory amino acids

1977 ◽  
Vol 55 (6) ◽  
pp. 1387-1390 ◽  
Author(s):  
J. F. MacDonald ◽  
A. Nistri ◽  
A. L. Padjen
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Firing Rate ◽  
Aspartic Acid ◽  
Excitatory Amino Acids ◽  
Neuronal Firing ◽  
Field Stimulation ◽  
Spinal Interneurones ◽  
Depressant Action ◽  
Derivatives Of

The effect of iontophoretically applied kainic acid diethylester (KDEE) on the firing rate of feline spinal interneurones was investigated and compared with the action of glutamic acid diethylester (GDEE) and aspartic acid diethylester (ADEE). All these esters reversibly reduced spontaneous neuronal firing and increased spike height, KDEE being the most active of this group. KDEE decreased responses to glutamate, acetylcholine, and peripheral field stimulation, showing that its depressant action is not due to a selective antagonism of an excitatory putative transmitter.

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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