Threonine aspartic acid

A linear extrapolation to zero-time of hydrolysis based on zero-order kinetics has been used to estimate the destruction of each amino acid (Smith and Stockell, 1954 Wilcox et al. 1957). In contrast, Hirs et al. (1954) measured the destruction of amino acids in a mixture of serine, threonine, aspartic acid, and glutamic acid and showed that first-order kinetics are applicable to the destruction observed. 

With the help of one- and two-dimensional TLC on sihca gel G, Dimillier and Trout [29] have observed increases in concentration of histidine, prohne, hydroxyproline, serine, threonine, aspartic acid, glutamic acid and tryptophan in blood during extracorporal circulation this increase was proportional to the duration of the extracorporal circulation. Through TLC on sihca gel layers with the solvent n-butanol-acetic acid-water (60 + 15 + 15), V. Euler and co-workers (40) have been able to isolate from the tumour serum of the rat, after precipitation of proteins with methanol, a substance of hJ /-value of 23 which was present at much lower concentration in the normal serum. By chromatographing again in two different solvents it could be identified as glycine. 

M hydrochloric acid at 107°C for 18 hr. The hydrolysate contained tryptophan, valine, glycine, proline, threonine, aspartic acid, and histidine in the (nearest integer) ratio of 1 1 1 1 2 2 1. The amino-terminal residue of the flavin peptide was found to be aspartic acid by the subtractive Edman method, with glycine as the next residue. Hydrolysis of the flavin peptide with 6 M hydrochloric acid for 17 hr at 95°C gave a histidylflavin which was purified by thin layer chromatography. Histidine was liberated from this histidylflavin by incubation at 125°C in 6 M hydrochloric acid. 

It is a peptide containing 27 amino acid residues containing the amino acids L-histidine (His) L-aspartic acid (Asp) L-serine (Ser) glycine (Gly) L-threonine (Thr) L-phenyl-alanine (Phe) L-glutamic acid (Glu) L-glutamine [Glu(NHj)] L-leucine (Leu) L-arginine (Arg) L-alanine (Ala) and L-valinamide (Va -NHj). 

This procedure works well with alanine, valine, threonine, iso leucine, glycine, leucine, proline, serine, aspartic acid, cystine, methionine, phenylalanine, tyrosine, ornithine, and lysine. 

The structures predicted for the fast and slow Ca -ATPase (Fig. 1) are 84 /o identical [8], There are 164 differences in the amino acid sequences between the two isoenzymes, 66 of which are conservative replacements, involving substitution of serine for threonine, aspartic for glutamic, lysine for arginine, or interchanges between aromatic or hydrophobic amino acids [8],... 

Moser et al. (1968) (one of the co-authors was Clifford Matthews) reported a peptide synthesis using the HCN trimer aminomalonitrile, after pre-treatment in the form of a mild hydrolysis. IR spectra showed the typical nitrile bands (2,200 cm ) and imino-keto bands (1,650 cm ). Acid hydrolysis gave only glycine, while alkaline cleavage of the polymer afforded other amino acids, such as arginine, aspartic acid, threonine etc. The formation of the polymer could have occurred according to the scheme shown in Fig. 4.9. 

Yeast strains are grown on either standard yeast extract, peptone, glucose media (YPD) (1% (w/v) yeast extract, 2% (w/v) bactopeptone, and 2% (w/v) glucose) and supplemented with the appropriate antibiotic, or in synthetic complete media (SCD media) (0.17% (w/v) yeast nitrogen base. 0.5% (w/v) ammonium sulphate, 2% (w/v) glucose, and supplemented with 20 mg/1 arginine, 100 mg/1 aspartic acid, 100 mg/1 glutamine, 30 mg/1 isoleucine, 30 mg/llysine, 20 mg/1 methionine, 50 mg/1 phenylalanine, 400 mg/lserine, 200 mg/1 threonine, 30 mg/1 tyrosine, and 150 mg/1 valine. When needed, the media was also supplemented with 20 mg/1 adenine, 10 mg/1 leucine, 60 mg/1 histidine, 60 mg/1 tryptophan, and 20 mg/1 uracil). 

The interaction with both synthetic and naturally occurring amino acids has been studied extensively glycine (138, 173, 219-221), a-(173, 219) and /3-alanine (138, 220), sarcosine (219), serine (222), aspartic acid (138, 173, 222-226), asparagine (222), threonine (222), proline (219), hydroxyproline (219), glutamic acid (138, 222-225), glutamine (222), valine (219, 227), norvaline (219), methionine (222, 226), histidine (228, 229), isoleucine (219), leucine (219, 230), norleu-cine (219), lysine (222), arginine (222), histidine methyl ester (228), phenylalanine (138, 222), tyrosine (222), 2-amino-3-(3,4-dihydroxy-phenyl jpropanoic acid (DOPA) (222), tryptophan (222), aminoiso-butyric acid (219), 2-aminobutyric acid (219,231), citrulline (222), and ornithine (222). 

The amounts of single amino acids excreted in urine in the conjugated form, as determined independently by Stein and Muting, are given in Tables 1 and 2. According to Stein, glycine, glutamic acid, aspartic acid, histidine, and proline are quantitatively the most important amino acids liberated in the course of urine hydrolysis. Serine, lysine, tyrosine, cysteine and cystine, threonine, alanine, valine, phenylalanine, and leucine are... 

Considerable amounts of glutamic acid, glycine, and alanine, as well as smaller quantities of aspartic acid, serine, threonine, basic amino acids, leucine, phenylalanine, and cystine have been demonstrated in a total hydrolyzate of the nondiffusible fraction by Boulanger et al. (BIO). Using Deacidite resin, they separated this material into two polypeptide fractions, acid and alkaline, and found that glutamic acid, aspartic acid, leucine, and certain cystine derivatives were the chief constituents of the former, whereas the latter contained considerable amounts of glycine, basic amino acids, and alanine. 

By means of a procedure described above, Hanson and Fittkau (HI) isolated seventeen different peptides from normal urine. One of them, not belonging to the main peptide fraction, consisted of glutamic acid, and phenylalanine with alanine as the third not definitely established component. The remaining peptides contained five to ten different amino acid residues and some unidentified ninhydrin-positive constituents. Four amino acids, i.e., glutamic acid, aspartic acid, glycine, and alanine, were found in the majority of the peptides analyzed. Twelve peptides contained lysine and eight valine. Less frequently encountered were serine, threonine, tyrosine, leucine, phenylalanine, proline, hydroxyproline, and a-aminobutyric acid (found only in two cases). The amino acid composi-... 

Small side chains (SSC) =glycine+alanine+serine, Polar chains (PC) =aspartic acid+threonine+serine+glutamic acid+tyrosine+lysine +histidine+arginine. 

Figure 2.9. Amino acid sequences of human defensins. The conserved positions of six cysteine residues are shown in hatched boxes. Abbreviations A, alanine C, cysteine D, aspartic acid E, glutamic acid F, phenylalanine G, glycine H, histidine I, isoleucine K, lysine L, leucine M, methionine N, asparagine P, proline Q, glutamic acid R, arginine S, serine T, threonine V, valine W, tryptophan Y, tyrosine.

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