scholarly journals Separation of two forms of rabbit metallothionein by isoelectric focusing

1972 ◽  
Vol 126 (3) ◽  
pp. 491-498 ◽  
Author(s):  
G F Nordberg ◽  
M. Nordberg ◽  
M. Piscator ◽  
O. Vesterberg
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Isoelectric Focusing ◽  
Amino Acid Analysis ◽  
Cadmium Chloride ◽  
Small Difference ◽  
Isoelectric Points ◽  
Main Protein ◽  
Similar Content ◽  
The One

Rabbits were given repeated injections of cadmium chloride. Cadmium- and zinc-containing protein fractions were obtained from the livers of these animals by precipitation procedures and Sephadex G-75 chromatography. The protein thus obtained showed several characteristics similar to those of the earlier described protein metallothionein. Further separation by isoelectric focusing showed two main protein peaks with isoelectric points at 3.9 and 4.5 respectively. Amino acid analysis of these two forms showed similar content of most amino acids [residues per cent.: cysteine (28%), aspartate (8%), threonine (5–6%), serine (12%), glycine (7%), alanine (13%), methionine (2%), isoleucine (2%)] but with a small difference in content of lysine (12 and 13% respectively), proline (9 and 5% respectively) and glutamate (2 and 4% respectively). The two forms of the protein both contained cadmium, but only the one with pI4.5 contained also significant amounts of zinc.

scholarly journals A Practical Approach to the Investigation of Amino Acid Disorders

1988 ◽  
Vol 25 (2) ◽  
pp. 129-141 ◽  
Author(s):  
M A Edwards ◽  
S Grant ◽  
A Green
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Practical Approach ◽  
The Common ◽  
Common Problems

We have, in this paper, highlighted some of the common problems in amino acid analysis in our experience and listed the possible causes for increases in specific amino acids in urine—together with guidance on appropriate follow-up investigations.

Comparison of Interlaboratory Variation in Amino Acid Analysis and Rat Growth Assays for Evaluating Protein Quality

1985 ◽  
Vol 68 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Ghulam Sarwar ◽  
Robert Blair ◽  
Mendel Friedman ◽  
Michael R Gumbmann ◽  
Ross L Hackler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Protein Quality ◽  
Essential Amino Acids ◽  
Quality Indices ◽  
Protein Ratio ◽  
Protein Sources ◽  
Rat Growth ◽  
Positive Correlations

Abstract Estimates of inter- and intralaboratory variation of protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) were compared with those of amino acid analysis in the same batches of 7 protein sources (ANRC casein, egg white solids, minced beef, soy assay protein, rapeseed protein concentrate, pea flour, and whole wheat flour). Interlaboratory variation (estimated as between-laboratories coefficients of variation, CV) of NPR and RNPR (up to 6.0%) was lower than that of PER (up to 20.2%) and RPER (up to 18.5%). The interlaboratory determination of NPR and RNPR was also more reproducible than that of most essential amino acids (CV up to 10.0%), especially tryptophan (CV up to 23.7%), cystine (CV up to 17.6%), and methionine (CV up to 16.1%). Intralaboratory variation (estimated as within-laboratories CV) of amino acid analysis (up to 4.7%), however, was comparable to that of protein quality indices in most protein sources (up to 6.0%). The significant (P <0.01) positive correlations (r = 0.68-0.74) between amino acid scores and protein quality indices based on rat growth were further improved when amino acid scores were corrected for digestibility of protein (r = 0.73-0.78) or individual amino acids (r = 0.79- 0.82).

scholarly journals Creation of a Broad-Range and Highly Stereoselectived-Amino Acid Dehydrogenase for the One-Step Synthesis ofd-Amino Acids

2006 ◽  
Vol 128 (33) ◽  
pp. 10923-10929 ◽  
Author(s):  
Kavitha Vedha-Peters ◽  
Manjula Gunawardana ◽  
J. David Rozzell ◽  
Scott J. Novick
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Dehydrogenase ◽  
Amino Acid Dehydrogenase ◽  
One Step ◽  
The One

scholarly journals Bakerian lecture - Amino-acid analysis and the structure of proteins

1942 ◽  
Vol 131 (863) ◽  
pp. 136-160 ◽  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Nutritive Value ◽  
Analytical Data ◽  
Seed Proteins ◽  
Decomposition Products ◽  
First Time ◽  
Structure Of Proteins

In recent years the X-ray crystallographers have made remarkable advances in the interpretation of protein structure, and it is becoming more and more evident that a stage has been reached when their views need to be reconciled with data obtained from accurate amino-acid analysis of the proteins concerned. In all too many cases these data are, unfortunately, not yet available, and the reason why the analyst cannot supply them at short notice is due not so much to the com­plexity of the problem—which he has never sought to minimize—but to the fact that many of the more important methods of analysis in current use are an inheritance from an earlier period when such accuracy as is now demanded would have been considered almost impossible of achievement. From about 1840 until 1900, following the lead given by Liebig and later by Ritthausen, the attention of protein chemists was centred chiefly on the prepara­tion and characterization of various animal and seed proteins; as substances of physiological interest their enzymic digestion products were studied in elaborate detail by Kühne, but little attention was paid to the ultimate decomposition products, the amino-acids, in spite of the fact that Ritthausen as early as 1872 had pointed out that the proportions in which these occur might be characteristic of the protein concerned. The enunciation by Hofmeister and Fischer of the peptide hypothesis in 1901 emphasized for the first time the fundamental importance of the amino-acids, and a most fruitful period followed in which attention became almost exclusively focused on these products. Under the inspiring leadership of Fischer himself great improvements were effected in the separation and identification of the amino-acids, so that by about 1915 reasonably good analyses were available for most of the better-known proteins. Though far from complete, the analytical data showed quite clearly that proteins could differ widely in composition, and in many cases it was possible to correlate composition with nutritive value. Such an aim was, indeed, the incentive behind much of the work of this period.

scholarly journals 60 YEARS OF POMC: Lipotropin and beta-endorphin: a perspective

2016 ◽  
Vol 56 (4) ◽  
pp. T13-T25 ◽  
Author(s):  
D G Smyth
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Structure And Function ◽  
Biologically Active ◽  
Molecular Endocrinology ◽  
And Function ◽  
The Brain ◽  
Quantitative Amino Acid Analysis

Many important fields of research had a humble origin. In the distant past, A J P Martin’s discovery that amino acids could be separated by paper chromatography and Moore and Stein’s use of columns for quantitative amino acid analysis provided the first steps towards the determination of structure in complex biologically active molecules. They opened the door to reveal the essential relationship that exists between structure and function. In molecular endocrinology, for example, striking advances have been made by chemists with their expertise in the identification of structure working with biologists who contributed valuable knowledge and experience. Advantage was gained from the convergence of different background, and it is notable that the whole is greater than the sum. In the determination of structure, it may be recalled that four of the world’s great pioneers (Archibald Martin, Rodney Porter, Fred Sanger and Vincent du Vigneaud) were acknowledged for their fundamental contributions when individually they were awarded the Nobel Prize. They foresaw that the identification of structure would prove of outstanding importance in the future. Indeed, study of the structures of β-endorphin and enkephalin and the different forms of opiate activity they engender has led to a transformation in our understanding of chemical transmission in the brain.

scholarly journals Hydrolysis of the Peptide Bond and Amino Acid Modification with Hydriodic Acid

1971 ◽  
Vol 24 (4) ◽  
pp. 1235 ◽  
Author(s):  
AS Inglis ◽  
PW Nicholls ◽  
CM Roxburgh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Boiling Point ◽  
Amino Acid Analysis ◽  
Peptide Bond ◽  
Hydriodic Acid ◽  
Acid Modification ◽  
Amino Acid Modification ◽  
Hydrolysis Of

Reaction of hydriodic acid with peptides and proteins has been studied. At the boiling point, hydrolysis of the peptide bond, particularly stable bonds linking valine and isoleucine residues, is facile. Several amino acids react with constantboiling hydriodic acid but the only reactions detrimental to the amino acid analysis are the reduction of serine with concomitant formation of alanine, and the destruction of tryptophan. Gentler conditions of hydrolysis with diluted hydriodic acid are required for analysis of serine. Good results for analysis of proteins for amino acids may be obtained after a 6-hr hydrolysis period.

Structural Changes in Prothrombin during Activation: A Theory

1970 ◽  
Vol 23 (01) ◽  
pp. 026-036 ◽  
Author(s):  
Walter H. Seegers ◽  
Genesio Murano ◽  
Lowell McCoy
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Structural Changes ◽  
Polypeptide Chain ◽  
Disulfide Bridge ◽  
Single Chain ◽  
Analytical Reagents ◽  
Terminal Amino ◽  
The One ◽  
Autoprothrombin C

SummaryProperties of the thrombin zymogen are quite different when in the form of prothrombin complex, DEAE-prothrombin (prothrombin) or prethrombin. When removed from the prothrombin complex, prothrombin spontaneously became refractory to the two-stage analytical reagents. No new N-terminal amino acids formed in association with this activation. A first step in prothrombin activation might be related to conformation. Repeatedly one mole of alanine was found as N-terminal amino acid for prothrombin and it is thus a single chain protein. Prethrombin did not have this alanine, but lysine and threonine, were found. Prethrombin, like thrombin, thus had two chains. After the conversion of prethrombin to thrombin with purified autoprothrombin C, a new N-terminal alanine amino acid was found attached to a peptide. Additionally peptides with N-terminal serine, lysine, and glycine were found. Threonine and isoleucine were again found as the N-terminal amino acids for 3.7 S thrombin and 3.2 S thrombin. As a working hypothesis, a perspective on the possible structure of prothrombin is outlined on the basis that it contains two moles of thrombin. Prethrombin probably forms when Ala1-peptide splits from a polypeptide chain which forms a loop held together by a disulfide bridge. Proteolysis probably also occurs in this loop. The postulated disulfide bridge would be the one which holds the A and B chains of thrombin together. In the conversion of prethrombin to thrombin, the first mole of thrombin would be set free. Then the Ala2-peptide released might correspond to the Ala1-peptide removed when prethrombin originally formed. Ala2-peptide thus would be related to the second mole of thrombin which could arise by further proteolysis including a split in the loop held together by a disulfide bridge. It is postulated that acidic peptides are attached to the main prothrombin polypeptide chain, to prethrombin, and to 3.7 S thrombin as satellite material.

scholarly journals Properties of cadmium-binding proteins in rat testes. Characteristics unlike metallothionein

1985 ◽  
Vol 231 (2) ◽  
pp. 279-283 ◽  
Author(s):  
J T Deagen ◽  
P D Whanger
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Binding Proteins ◽  
Gel Filtration ◽  
Weanling Rats ◽  
Liver And Kidney ◽  
The Individual ◽  
Two Peaks ◽  
Dietary Cadmium

Since the exposure of rats to cadmium causes zinc to accumulate in metallothionein in liver and kidney but not in a similar protein in the testes, the properties of the low-Mr cadmium-binding proteins were investigated in rat testes. Weanling rats that had been given dietary cadmium for 6 weeks were injected with 109CdCl2 and subsequently killed, and the 109Cd-labelled low-Mr proteins from testes were purified. The pooled low-Mr cadmium-containing fractions from the gel-filtration (Sephadex G-75) columns were eluted through DEAE-Sephacel columns, yielding two peaks. Each of the individual peaks from this Sephacel column was further purified by rechromatography on DEAE-Sephacel and on Bio-Gel P-10 columns. Amino acid analysis of the two purified proteins revealed a low cysteine (about 3%) content, with aspartate, glutamate and glycine as the predominant amino acids. Thus these low-Mr cadmium-binding proteins induced by cadmium in rat testes do not appear to be metallothionein.

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