Conversion of phenylalanine to tyrosine by microorganisms

1968 ◽  
Vol 14 (5) ◽  
pp. 573-578 ◽  
Author(s):  
P. Chandra ◽  
L. C. Vining
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Marine Bacterium ◽  
Specific Activities ◽  
Hydrolysis Of ◽  
Preferential Incorporation

Fourteen microorganisms of different genera were examined for their ability to convert L-phenylalanine directly to tyrosine. Comparison of the specific activities of phenylalanine, tyrosine, aspartic acid, and glutamic acid isolated after hydrolysis of cells grown in the presence of L-phenylalanine-U-14C indicated that p-hydroxylation of phenylalanine had occurred in all seven species of microfungi tested, and in the marine bacterium, Pseudomonas atlantica. In two basidiomycetes, two yeasts, an actinomycete, and a bacillus, there was no preferential incorporation of radioactivity into tyrosine.

Novel high-yield synthesis of .gamma. esters of glutamic acid and .beta. esters of aspartic acid by the copper-catalyzed hydrolysis of their diesters

1975 ◽  
Vol 40 (22) ◽  
pp. 3287-3288 ◽  
Author(s):  
R. L. Prestidge ◽  
D. R. K. Harding ◽  
J. E. Battersby ◽  
W. S. Hancock
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
High Yield ◽  
Hydrolysis Of

scholarly journals Aspartic Acid, Asparagine, Glutamic Acid, and Glutamine Contents of Wool and two Derived Protein Fractions

1971 ◽  
Vol 24 (3) ◽  
pp. 509 ◽  
Author(s):  
LA Holt ◽  
B Milligan ◽  
CM Roxburgh
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Leucine Aminopeptidase ◽  
Ribonuclease A ◽  
Protein Fractions ◽  
Hydrolysis Of ◽  
Successive Reduction

A method is described for the hydrolysis of wool which entails successive reduction, carboxymethylation, and digestion with the three enzymes, Pronase, prolidase, and leucine aminopeptidase. The reliability of the method has been checked using two proteins of known composition, viz. ribonuclease A and insulin.

The metabolism of 14C-urea by white spruce seedlings in light and darkness

1973 ◽  
Vol 51 (6) ◽  
pp. 1197-1211 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Urease Activity ◽  
De Novo ◽  
White Spruce ◽  
Acid Synthesis ◽  
Transfer Rna ◽  
Ammonium Ions ◽  
Specific Activities

Weak urease activity was detected in 2-week-old white spruce seedlings. The addition of urea to these seedlings increased urease activity in light compared to darkness. Urease was localized in the cytoplasm mainly in the epidermal cells, and to a lesser extent in vascular tissues and at the shoot apex.In light, the early products of 14C-urea indicated the release of 14C-carbon dioxide and ammonium ions. Radioactivity appeared in the anionic and neutral fractions and then in alanine, serine, and glycine, just as in the fixation of 14C-bicarbonate. By 4 h most radioactivity resided in glutamic acid and alanine. This pattern was associated with increased protein synthesis, and with high levels of free glutamine. Serine, glycine, alanine, and carbamyl aspartic acid had high specific activities.In darkness, radioactivity in alanine persisted, but levels in serine, glycine, and protein were low. Most radioactivity eventually resided in asparagine. Radioactive urea and citrulline were kept at higher levels than in light. Glutamic acid, citrulline, and carbamyl aspartic acid had the greatest specific activities. In light and darkness, carbamyl derivatives were formed more readily from 14C-urea than from 14C-bicarbonate.Carbamyl phosphate was implicated as a precursor of citrulline and arginine as well as for carbamyl aspartic acid. In light, radioactivity was recovered from ribosomal (25, 23, 18, 16, and 5 S) and transfer RNA (4 S). This resided mainly in uracil and cytosine. By contrast, in DNA, radioactivity was recovered mainly from thymine, cytosine, and 5-methylcytosine. In rapidly growing seedlings, urea contributed to de novo nucleic acid synthesis mainly through pyrimidine pathways via carbamyl aspartic acid.

Uptake of Dipeptides Containing Basic and Acidic Amino Acids by Rat Small Intestine in Vitro

1972 ◽  
Vol 43 (6) ◽  
pp. 823-837 ◽  
Author(s):  
D. Burston ◽  
Jill M. Addison ◽  
D. M. Matthews
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Tissue Uptake ◽  
Acidic Amino Acids ◽  
Hydrolysis Of

1. The characteristics of transport and hydrolysis of twenty-two dipeptides containing basic and acidic amino acids by rat ileal rings were investigated in vitro. The peptides included combinations of basic and neutral, basic and basic, basic and acidic, acidic and acidic, and acidic and neutral amino acids. 2. All peptides studied were removed intact from the bulk phase of the incubation medium, though, in general, only free amino acids appeared in the tissue. Uptake of one or both constituent amino acids was greater from the peptide than from the equivalent amino acid or amino acid mixture in the case of at least one peptide from each group and in eighteen of the twenty-two peptides studied. In general, there was no relationship between the extent of uptake of amino acids from peptides and the extent of their hydrolysis by the system. The results support the hypothesis that there is more than one mode of uptake of amino acids from peptides. 3. Hydrolysis of γ-glutamyl-l-glutamic acid by intact intestine or intestinal homogenate was slight, and intact peptide was taken up by the tissue. Uptake of free glutamic acid from this peptide was poor. Comparison of γ-glutamyl-l-glutamic acid with three other slowly hydrolysed dipeptides, glycyl-d-valine, sarcosylglycine and glycylsarcosine, suggested that all four were transported into the mucosal cells and hydrolysed intracellularly. The results indicate that the presence of a γ-linkage or a d-amino acid, or methylation of the free amino group as in sarcosylglycine, impair both transport and hydrolysis of peptide, but that attachment of a methyl group to the N of the peptide bond, as in glycylsarcosine, impairs hydrolysis but has no effect on peptide transport. 4. l-Aspartic acid and l-glutamic acid were extensively transaminated by the intestine, whether presented as free amino acids or in peptides. Evidence was obtained suggesting that production of alanine from aspartic acid resulted from direct transamination of aspartic acid with pyruvic acid, rather than from a sequence of two reactions involving aspartate and alanine aminotransferases. 5. The results show that more rapid uptake of amino acids from peptides than from free amino acids is not confined to peptides made up of neutral amino acids, and probably occurs with many small peptides. Uptake of lysine and the dicarboxylic amino acids, which are particularly slowly absorbed from free solution, was much greater from several dipeptides than from the free amino acids. The results suggest the importance of mucosal peptide uptake in protein absorption.

An extracellular proteolytic enzyme from Scopalariopsis brevicaulis. II. Hydrolysis of poly amino acids

1972 ◽  
Vol 18 (7) ◽  
pp. 1165-1167 ◽  
Author(s):  
Kartar Singh ◽  
Claude Vézina
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Proteolytic Enzyme ◽  
Ph Values ◽  
Optimum Ph ◽  
Extracellular Proteolytic Enzyme ◽  
Scopulariopsis Brevicaulis ◽  
Hydrolysis Of

Scopulariopsis brevicaulis protease hydrolyzed poly-L-lysine and poly-L-glutamic acid; optimum pH values for hydrolysis were 10.6 and 4.7 respectively. Final products of poly-L-lysine digestion by the protease were intermediate peptides from tetramer upwards. Pentalysine was not hydrolyzed by the enzyme. The protease had no action on poly-L-aspartic acid, poly-L-alanine, poly-L-glycine, poly-L-valine, or poly-L-leucine.

The Hydrolysis of Some N-Acylaspartic and N-Acylglutamic Monoamides in Dilute Mineral Acid

1975 ◽  
Vol 53 (11) ◽  
pp. 1137-1144 ◽  
Author(s):  
M. Ali ◽  
J. B. Capindale
Keyword(s):  
Hydrochloric Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Rate Constants ◽  
Mineral Acid ◽  
First Order ◽  
Order Rate ◽  
Succinamic Acid ◽  
Aqueous Hydrochloric Acid ◽  
Hydrolysis Of

The release of ammonia by hydrolysis of N-benzoyl-L-asparagine, glycyl-DL-asparagine, L-asparagine, and succinamic acid, and of aniline from N-benzoyl-L-glutamic-α-anilide, N-benzoyl-L-aspartic-α-anilide, L-aspartic-α-anilide, and the monoanilides of succinic and glutaric acids is first-order with respect to substrate in dilute (0.4–0.03 M) aqueous hydrochloric acid at 100 °C. The first-order rate constants (kobs) for these reactions can be expressed as kobs = kintra + k2[H+]. The above hydrolyses are used as models for developing a tentative mechanism to account for the selective release of aspartic acid from proteins under these conditions. The data are also used to suggest reasons why glutamic acid is not released with equal facility.

scholarly journals Structure and enzymic activity of ribonuclease-A esterified at glutamic acid-49 and aspartic acid-53

1978 ◽  
Vol 173 (3) ◽  
pp. 821-830 ◽  
Author(s):  
A. Seetharama Acharya ◽  
Belur N. Manjula ◽  
Paul J. Vithayathil
Keyword(s):  
Methyl Ester ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Spectral Characteristics ◽  
Dimethyl Ester ◽  
Limited Proteolysis ◽  
Ribonuclease A ◽  
Enzymic Activity ◽  
S Protein ◽  
Hydrolysis Of

The dimethyl ester of bovine pancreatic ribonuclease-A (dimethyl RNAase-A), the initial product of esterification of RNAase-A in anhydrous methanolic HCl, was isolated in a homogeneous form. The two carboxy functions esterified in this derivative are those of glutamic acid-49 and aspartic acid-53. There were no changes in the u.v.-absorption spectral characteristics, the accessibility of the methionine residues, the resistance of the protein to proteolysis by trypsin and the antigenic behaviour of RNAase-A as a result of the esterification of these two carboxy groups. Dimethyl RNAase-A exhibited only 65% of the specific activity of RNAase-A, but still had the same Km value for both RNA and 2′:3′-cyclic CMP. However, the Vmax. was decreased by about 35%. On careful hydrolysis of the methyl ester groups at pH9.5, dimethyl RNAase-A was converted back into RNAase-A. Limited proteolysis of dimethyl RNAase-A by subtilisin resulted in the formation of an active RNAase-S-type derivative, namely dimethyl RNAase-S, which was chromatographically distinct from dimethyl RNAase-A and had very nearly the same enzymic activity as dimethyl RNAase-A. Fractionation of dimethyl RNAase-S by trichloroacetic acid yielded dimethyl RNAase-S-protein and dimethyl RNAase-S-peptide, both of which were inactive by themselves but regenerated dimethyl RNAase-S when mixed together. Dimethyl RNAase-A-peptide was identical with RNAase-S-peptide. RNAase-S-protein could be generated from dimethyl RNAase-S-protein by careful hydrolysis of the methyl ester groups at pH9.5. The interaction of dimethyl RNAase-S-protein with RNAase-S-peptide appears to be about 4-fold weaker than that between the RNAase-S-protein and RNAase-S-peptide. Conceivably, the binding of the S-peptide ‘tail’ of dimethyl RNAase-A with the remainder of the molecule is similarly weaker than that in RNAase-A, and this brings about subtle changes in the geometrical orientation of the active-site amino acid residues of these modified methyl ester derivatives. It is suggested that these changes could be responsible for the generation of the catalytically less-efficient RNAase-A and RNAase-S molecules (dimethyl RNAase-A and dimethyl RNAase-S respectively).

scholarly journals Dietary glutamic acid and aspartic acid as biomarkers for predicting diabetic retinopathy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
So Young Park ◽  
Jieun Kim ◽  
Jung Il Son ◽  
Sang Youl Rhee ◽  
Do-Yeon Kim ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Education Level ◽  
Screening Rate ◽  
Food Records ◽  
Acid Intake ◽  
Lower Education Level ◽  
Lower Education

AbstractThe screening rate of diabetic retinopathy (DR) is low despite the importance of early diagnosis. We investigated the predictive value of dietary glutamic acid and aspartic acid for diagnosis of DR using the Korea National Diabetes Program cohort study. The 2067 patients with type 2 diabetes without DR were included. The baseline intakes of energy, glutamic acid and aspartic acid were assessed using a 3-day food records. The risk of DR incidence based on intake of glutamic acid and aspartic acid was analyzed. The DR group was older, and had higher HbA1c, longer DM duration, lower education level and income than non-DR group (all p < 0.05). The intake of total energy, glutamic acid and aspartic acid were lower in DR group than non-DR group (p = 0.010, p = 0.025 and p = 0.042, respectively). There was no difference in the risk of developing DR according to the intake of glutamic acid and ascorbic acid. But, aspartic acid intake had a negative correlation with PDR. Hence, the intake of glutamic acid and aspartic acid did not affect in DR incidence. However, lower aspartic acid intake affected the PDR incidence.

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