scholarly journals Studies on Separation of Amino Acids and Related Compounds. V. A Racemization Test in Peptide Synthesis by the Use of an Amino Acid Analyzer

1971 ◽  
Vol 44 (12) ◽  
pp. 3391-3395 ◽  
Author(s):  
Nobuo Izumiya ◽  
Masako Muraoka ◽  
Haruhiko Aoyagi
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Amino Acid Analyzer ◽  
Related Compounds

Amino acid concentrations in serum and aqueous humor from subjects with extreme myopia or senile cataract.

1988 ◽  
Vol 34 (8) ◽  
pp. 1610-1613 ◽  
Author(s):  
J A Wuu ◽  
L Y Wen ◽  
T Y Chuang ◽  
G G Chang
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Humor ◽  
Normal Subjects ◽  
Senile Cataract ◽  
Amino Acid Analyzer ◽  
Almost All ◽  
Related Compounds ◽  
Amino Acid Concentrations ◽  
Cataract Patients

Abstract With an amino acid analyzer, we measured amino acids and related compounds in serum and aqueous humor from normal Chinese and some patients with extreme myopia or senile cataracts. Forty peaks were well resolved, and their areas were used to quantify each compound. In the myopic patients, glutamate, alpha-aminoadipate, and methionine concentrations in serum were 10-fold those in the normal subjects. Values for most of the other amino acids and related compounds were also higher in myopic patients' sera. In the cataract patients, concentrations of most of these compounds were lower in serum but higher in aqueous humor than for the normal subjects. Tryptophan was present in significant amounts in sera from the normal subjects, but was not detectable in the senile-cataract patients. The ratio of amino acid concentration in aqueous humor to that in the serum (Ch/Cs) was higher in the cataract patients than in normal subjects for almost all of the compounds we measured.

scholarly journals Determination of Methylated Basic Amino Acids with the Amino Acid Analyzer

1973 ◽  
Vol 248 (7) ◽  
pp. 2387-2391 ◽  
Author(s):  
Gladys E. Deibler ◽  
Russell E. Martenson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basic Amino Acids ◽  
Amino Acid Analyzer

Fmoc amino acid fluorides in peptide synthesis — Extension of the method to extremely hindered amino acids

1996 ◽  
Vol 37 (31) ◽  
pp. 5483-5486 ◽  
Author(s):  
Holger Wenschuh ◽  
Michael Beyermann ◽  
Rüdiger Winter ◽  
Michael Bienert ◽  
Dumitru Ionescu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Amino Acid Fluorides ◽  
Acid Fluorides

scholarly journals AMINO ACID COMPOSITION OF LEAVES OF THREE SPECIES OF ARTEMISIA L. GROWING IN THE ELTON REGION

2021 ◽  
pp. 219-225
Author(s):  
Галина Табаленкова
Keyword(s):  
Amino Acids ◽  
Czech Republic ◽  
Amino Acid ◽  
Dry Weight ◽  
Biologically Active ◽  
Raw Material ◽  
Buffer System ◽  
Amino Acid Analyzer ◽  
Growing Conditions ◽  
High Level

The results of studies of the qualitative composition and quantitative content of amino acids (AAs) in the leaves of three plant species of the genus Artemisia, widespread in the Elton region, were presented. Protein AAs were determined on an AAA T-339 amino acid analyzer (Czech Republic) after hydrolysis of a sample in 6N HCl at 105 °C for 24 h, free AAs – on an AAA-400 amino acid analyzer (Czech Republic) in a lithium buffer system. The protein AAs amount varied from 66 mg / g in A. lerchiana to 113 mg / g dry weight in A. santonica. 17 AAs were found in composition of these species, aspartic and glutamic acids were dominant. The content of free AAs varied from 4.4 mg / g in A. santonica to 8.3 mg / g dry weight in A. pauciflora. 14 AAs have been identified, among them proline was the predominant free AA. The share of proline was 75-81% of the total free AAs. Among the minor components, 3-4 compounds with a content above 2% dominated. The free AAs contain 3 non-proteinogenic ones (ornithine, citruline, and γ-aminobutyric acid). A. lerchiana and A. pauciflora species were similar in protein and free amino acids, probably due to the same growing conditions. A high level of free proline, together with a complex of biologically active substances in Artemisia species, which grow abundantly in the Elton region, allow to consider the possibility of their use as a medicinal raw material.

Chelating polymers. I. The synthesis and acid dissociation behavior of several N-(p-vinylbenzenesulfonyl)-substituted diaminopolyacetic acid monomers, monomeric analogues, and related intermediates

1970 ◽  
Vol 48 (1) ◽  
pp. 163-175 ◽  
Author(s):  
R. M. Genik-Sas-Berezowsky ◽  
I. H. Spinner
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dissociation Constants ◽  
Acid Dissociation ◽  
Inductive Effects ◽  
Cyclic Amide ◽  
Amino Acid Analogues ◽  
Related Compounds ◽  
Chelating Polymers ◽  
Made In

Two new chelating monomers, N-(p-vinylbenzenesulfonyl)1,2-diaminoethane-N′,N′-diacetic (SS-EDDA) and -N,N′,N′-triacetic (SS-ED3A) acids, as well as several monomeric analogues and related intermediates have been prepared. In addition, 2-oxo-1-piperazine acetic (S-KP), 3-oxo-1-piperazine acetic (U-KP), and 2-oxo-1,4-piperazine diacetic (3-KP) acids have been synthesized and the interconvertibility between these cyclic amides and their unsubstituted linear amino acid analogues, ethylene-diamine-N,N′-diacetic (S-EDDA), -N,N-diacetic (U-EDDA), and -N,N,N′-triacetic (ED3A) acids respectively, was demonstrated.The acid dissociation constants of the various amino acids were determined potentiometrically at 25° and μ = 0.1 M(KNO3) and the results were compared with the hydrogen ion affinities of related compounds. Dissociation schemes were proposed for all the compounds based on these results. Rationalizations of the linear amino acid and the cyclic amide dissociation constants were made in terms of the effects of cyclization and the inductive effects of neighboring groups. These rationalizations were found to be helpful in clarifying the dissociation schemes previously proposed for several of the linear amino acids.

Formation and occurrence of N-malonylphenylalanine and related compounds in plants

1968 ◽  
Vol 46 (8) ◽  
pp. 797-806 ◽  
Author(s):  
N. Rosa ◽  
A. C. Neish
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Plant Species ◽  
Isolation Procedure ◽  
Plant Kingdom ◽  
Feeding Experiments ◽  
Leucine Isomers ◽  
Related Compounds

Shoots of barley seedlings when fed D-phenylalanine convert the amino acid to N-malonylphenylalanine. Some N-acetylphenylalanine is obtained at the same time but this may be an artifact of the isolation procedure since it is readily formed by decarboxylation of the malonylphenylalanine. Feeding experiments with the D- and L-isomers of phenylalanine, valine, leucine, isoleucine, tyrosine, tryptophan, alanine, and glutamic acid showed that barley shoots form the malonyl derivative from all the D-isomers whereas little, if any, is formed from the L-isomers. Similar experiments with phenylalanine and leucine isomers, using seven different plant species, showed that the ability to conjugate the D-isomers (but not the L-isomers) was found in all of the plants tested. It was also observed that the ether-soluble acidic conjugates of a variety of amino acids, possibly malonyl derivatives, occur widely throughout the plant kingdom.

A Preliminary Study of the Fixation Mechanism of Collagen Reaction with a Polyepoxy Fixative

1993 ◽  
Vol 16 (7) ◽  
pp. 537-544 ◽  
Author(s):  
R. Tu ◽  
R.C. Quijano ◽  
C.L. Lu ◽  
S. Shen ◽  
E. Wang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Great Promise ◽  
Fixation Time ◽  
Denaturation Temperature ◽  
Amino Acid Analyzer ◽  
Direct Indication ◽  
Preliminary Study ◽  
The Difference ◽  
Fixation Reaction

A new biomaterial has been developed by fixing native collagens with a polyepoxy compound (PC) fixative. Prior studies have shown that this biomaterial has comparable properties as compared to collagen fixed with glutaraldehyde (GA) and thus has a great promise for use as an implantable bioprosthesis. The purpose of this study was to understand the mechanism of the amino acids-PC reactions in the fixation process. Bovine arteries were fixed with PC under various pH, concentration and temperature conditions as a function of fixation time. Individual amino acid components in the fresh and the fixed arteries were assayed using a Beckman amino acid analyzer to determine the degree of tanning. The denaturation temperature (Td) was also measured on each sample. Since the denaturation temperature is a direct indication of cross-linking of individual amino acids with the fixative, the difference in the degree of tanning for the same increase in Td may be indicative of the quantity of the masked, non-cross-linked amino acids. The fixation reaction data indicated that not all amino acids were cross-linked upon contacting the PC fixative. Masking appeared to be more substantial with a fixation at higher pH values.

N-Methylamino acids in peptide synthesis. VII. Studies on the enantiomeric purity of N-methylamino acids prepared by various procedures

1977 ◽  
Vol 55 (5) ◽  
pp. 916-921 ◽  
Author(s):  
S. T. Cheung ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acid ◽  
Methyl Iodide ◽  
Peptide Synthesis ◽  
Liquid Ammonia ◽  
Silver Oxide ◽  
Sodium Hydride ◽  
Enantiomeric Purity ◽  
Amino Acid Analyzer ◽  
Pure Compounds ◽  
Optically Pure

The enantiomeric purity of N-methylamino acids and their derivatives obtained by various procedures has been examined by analysis with an amino-acid analyzer of the diastereomeric lysyl dipeptides formed by coupling them with a lysyl derivative. N-Benzyloxycarbonyl, and N-tert-butyloxycarbonyl,N-methylamino acids obtained by methylation of the parent derivative using sodium hydride and methyl iodide, and N-methylamino acids obtained by methylation of the p-toluenesulfonylamino acid followed by treatment with sodium in liquid ammonia, are optically pure. Compounds obtained by other procedures which include reductive alkylations or the use of silver oxide – methyl iodide are generally not optically pure.

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