scholarly journals DETERMINATION OF CERTAIN AMINO ACIDS IN CHYMOTRYPSINOGEN, AND ITS MOLECULAR WEIGHT

1941 ◽  
Vol 25 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Erwin Brand ◽  
Beatrice Kassell
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Osmotic Pressure ◽  
Amino Acid Analysis ◽  
Pressure Measurements ◽  
Sulfur Amino Acids ◽  
Sh Groups

1. A preparation of chymotrypsinogen, obtained from Dr. M. Kunitz, was analyzed for sulfur, the sulfur amino acids, tyrosine, and tryptophane. 2. The protein sulfur of chymotrypsinogen was accounted for as methionine, cysteine, and cystine. 3. A method is presented for calculating the minimum molecular weight of a protein from the distribution of the sulfur amino acids. In the case of chymotrypsinogen, the calculated minimum molecular weight was found to be the actual molecular weight. 4. The molecular weight of chymotrypsinogen is 36,700 by amino acid analysis as compared to 36,000 by osmotic pressure measurements of Kunitz and Northrop. Chymotrypsinogen contains per mol 17 atoms of sulfur, 3 residues of methionine, 4 of cysteine, 10 of half-cystine (i.e. 5 S—S linkages), 6 of tyrosine, and 10 of tryptophane. 5. The tryptophane content of chymotrypsinogen (5.51 per cent) is the highest of any protein so far on record. 6. Chymotrypsinogen contains no reactive SH groups, although it yields cysteine on hydrolysis. This may be due either to preformed but unreactive SH groups or to S—X groups. The term S—X group is used to denote the substitution of the sulfhydryl hydrogen by a constituent X; hydrolysis yields SH groups: S—X + HOH = SH + X—OH.

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.

Determination of Sulfur Amino Acids and Tryptophan in Foods and Food and Feed Ingredients: Collaborative Study

1988 ◽  
Vol 71 (3) ◽  
pp. 603-606
Author(s):  
Maryann C Allred ◽  
John L Macdonald
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Collaborative Study ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Protein Hydrolysis ◽  
Sulfur Amino Acids ◽  
Feed Ingredients ◽  
Food And Feed

Abstract Samples of 4 foods, 1 animal feed, isolated soy protein, and 0-lao toglobulin were analyzed by 9 laboratories to determine concentrations of cysteine as cysteic acid, methionine as methionine sulfone, and tryptophan. Sulfur amino acids were determined by AOAC method 43.A08-43.A13 for food and feed ingredients, in which samples are oxidized with performic acid before protein hydrolysis with 6N HC1. Tryptophan was determined after protein hydrolysis with 4.2N NaOH. In both methods, free amino acids were separated by ionexchange or reverse-phase chromatography. Each laboratory was provided with detailed methods and with sealed vials containing solutions of standards. Samples were analyzed in duplicate, and variation between laboratories was determined. Coefficients of variation between laboratories for the 6 samples ranged from 5.50 to 11.8% for methionine as methionine sulfoxide, 8.59 to 17.3% for cysteine as cysteic acid, and 3.87 to 16.1% for tryptophan. Amino acid recoveries were determined by analysis of β-lactoglobulin and were based on expected levels of each amino acid obtained from amino acid sequence data. The mean recovery of cysteine was 97% with a range of 88-119%. For methionine, mean recovery was 98% (range 89-115%) and for tryptophan, 85% (range 59-102%). Method 43.A08- 43.A13 for food and feed ingredients has been adopted official first action for determination of cysteine and methionine in processed foods. The alkaline hydrolysis method has been adopted official first action for determination of tryptophan in foods and food and feed ingredients

scholarly journals Response of broilers to digestible sulfur amino acids and threonine intake: maximum economic return

2020 ◽  
Vol 33 (4) ◽  
pp. 239-251
Author(s):  
Matheus De-Paula Reis ◽  
Mirella Cunha-Melaré ◽  
Gabriel Silva-Viana ◽  
Daniella C Zanardo-Donato ◽  
Nilva Kazue-Sakomura
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chicken ◽  
Bodyweight Gain ◽  
Sulfur Amino Acids ◽  
Gross Margin ◽  
Inclusion Level ◽  
Feed Costs ◽  
The Ideal

Background: The determination of amino acid supplements for broiler chicken requirements based on performance does not always reflect maximum profitability. Objective: To estimate the optimal levels of digestible threonine (Thr) and sulfur amino acids (SAA) in diets for broilers based on an economic analysis. Methods: Two dose-response assays were conducted, and each assay was divided into three phases: initial (1-14 days), grower (15-28 days), and finisher (29-42 days). Five hundred and sixty male Cobb 500® broilers were randomly distributed to seven treatments with increasing levels of the amino acid (SAA or Thr), with four replicates and 20 birds each. Bodyweight gain (BWG) and feed intake (FI) were used to fit a segmented model. Gross income (GI), total feed costs (TFC) and gross margin (GM) were calculated based on local values. Results: Increasing levels of amino acid elicited a response in BWG and FI for all evaluated phases. The estimates for maximum profit based on GI and TFC were 223, 504, and 975 mg SAA/bird/d, and 236, 696, and 1,042 mg Thr/bird/d in starter, grower and finisher phases, respectively. Conclusion: Varying the AA prices affected only slightly the economic optimal intake of Thr and sulfur amino acids. Despite market fluctuations, the economic approach presented in this study demonstrates to be a helpful tool to choose the ideal inclusion level of amino acids in the feed.

scholarly journals Taurine in Cerebrospinal Fluid in Friedreich's Ataxia

1978 ◽  
Vol 5 (1) ◽  
pp. 125-129 ◽  
Author(s):  
B. Lemieux ◽  
R. Giguere ◽  
A. Barbeau ◽  
S. Melancon ◽  
D. Shapcott
Keyword(s):  
Amino Acids ◽  
Cerebrospinal Fluid ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Amino Acid Analysis ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia

SUMMARY:In a previous study we reported low values of taurine and aspartic acid in the CSF of patients with Friedreich's ataxia, when the results were compared to the literature. Further studies have revealed that tinforetold difficulties with the advertised methodology of sequential multi-sample amino acid analysis were responsible for low values in the determination of these two amino acids in the small volumes necessary for CSF. A corrected method is presented. With the latter method the differences disappear for CSF taurine and aspartic acid, but they remain valid for the previously reported blood and urine values in Friedreich's ataxia. GABA levels are also normal in Friedreich's ataxia CSF.

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