Infrared spectra of microgram amounts of amino acid phenylthiohydantoins eluted from thin layers of silica gel

1968 ◽  
Vol 40 (2) ◽  
pp. 440-442 ◽  
Author(s):  
Marvin. Murray ◽  
Gerald Floyd. Smith
Keyword(s):  
Amino Acid ◽  
Silica Gel ◽  
Infrared Spectra ◽  
Thin Layers

Infrared spectra of N-acetyl-L-α-amino-acid N'-methylamides with aliphatic side chains in non-polar solvents

1981 ◽  
Vol 46 (3) ◽  
pp. 772-780 ◽  
Author(s):  
Jorga Smolíková ◽  
Jan Pospíšek ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Side Chains ◽  
Polar Solvents

Infrared spectra of the L-alanine (I), L-leucine (II), L-valine (III) and L-tert-leucine (IV) N-acetyl N'-methylamides were measured. Amides I-IV are not self associated in tetrachlormethane in the concentration 2 . 10-5 mol l-1 at room temperature and in tetrachloroethylene in the concentration 1.5 . 10-4 mol l-1 at temperatures above 65° C. True conformational changes are observable only with the least flexible amide IV which exists at room temperature in a C5 conformation. This conformational type is also highly populated in the valine derivative III, but is less important in the alanine and leucine derivatives I and II in which the intramolecularly bonded C7 and the distorted hydrogen-nonbonded conformations contribute seriously.

scholarly journals Chemical synthesis of all-trans-β-retinoyl phosphate

1976 ◽  
Vol 159 (3) ◽  
pp. 799-801 ◽  
Author(s):  
J P Frot-Coutaz ◽  
L M de Luca
Keyword(s):  
Retinoic Acid ◽  
Chemical Synthesis ◽  
Cellulose Acetate ◽  
Silica Gel ◽  
Absorption Maximum ◽  
Ammonium Acetate ◽  
Deae Cellulose ◽  
Thin Layers ◽  
Molar Ratio ◽  
Chloroform Methanol

all-trans-β-Retinoic acid is phosphorylated to retinoyl phosphate by bis(triethylamine) phosphate with yields of 10-15%. The product is soluble in methanol and is eluted from DEAE-cellulose acetate at a concentration of 0.1M-ammonium acetate in 99% (v/v) methanol. Its phosphate/retinoic acid molar ratio is 1. Retinoyl phosphate has an absorption maximum at 360nm in methanol, whereas retinoic acid has a maximum at 350 nm. The compound is hydrolysed at pH2 and pH13 for 20 min at 37 degrees C, but is relatively stable under the same conditions at pH4, 6, 8 and 10. Retinoyl phosphate (RF 0.1) can be separated from retinyl phosphate (RF 0.2) by chromatography on thin layers of silica gel in chloroform/methanol/water (60:25:4, by vol.).

Radiation Damage to Polypeptides and Proteins in the Solid State: Changes in Amino Acid Composition *

1981 ◽  
Vol 36 (3-4) ◽  
pp. 310-318 ◽  
Author(s):  
J. Seredynski ◽  
T. Söylemez ◽  
W. Baumeister
Keyword(s):  
Amino Acids ◽  
Electron Microscope ◽  
Amino Acid ◽  
Solid State ◽  
Trypsin Inhibitor ◽  
Concanavalin A ◽  
Thin Layers ◽  
Aminobutyric Acid ◽  
Sensitivity Pattern ◽  
State Changes

Thin layers of synthetic homopolypeptides (poly-α-Ala, -Arg, -Asn, -Asp, -Glu, -His, -Lys and -Tyr) and proteins (myoglobin, concanavalin A, trypsin-inhibitor) were irradiated under solid state conditions in an electron microscope with 100 keV electrons. Radiolytic changes were investigated by amino acid analysis. The results are discussed in terms of the relative radiosensitivities of the constituent amino acids, and possible topochemical effects on the sensitivity pattern emerging. An attempt is also made to trace at least some of the predominant pathways of amino acid transformation, namely the production of alanine and a-aminobutyric acid

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