Determination Of Tryptophan In Proteins Research Articles

Hydrochloric acid hydrolysis of proteins and determination of tryptophan by reversed-phase high-performance liquid chromatography

A simple method was developed for determination of tryptophan in proteins. Hydrolysis is achieved under reducing conditions, in 6 n hydrochloric acid containing 0.4% β-mercaptoethanol, at 110°C for 24 h. The phenylthiocarbamyl derivatives of the amino acids are separated by reversed-phase high-performance liquid chromatography, without any by-product interference. The recovery of tryptophan is complete. However, the method does not allow the determination of tryptophan in carbohydrate-rich biological samples.

Determination of tryptophan in proteins by pyrolysis gas chromatography

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of tryptophan in proteins by pyrolysis gas chromatographyNeil D. Danielson and L. B. RogersCite this: Anal. Chem. 1978, 50, 12, 1680–1683Publication Date (Print):October 1, 1978Publication History Published online1 May 2002Published inissue 1 October 1978https://doi.org/10.1021/ac50034a027RIGHTS & PERMISSIONSArticle Views108Altmetric-Citations35LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (497 KB) Get e-Alerts Get e-Alerts

Effect of high tyrosine content on the determination of tryptophan in protein by the acidic ninhydrin method. Application to chicken ovoinhibitor.

Colorimetric determination of tryptophan in intact proteins by the acidic ninhydrin method of Gaitonde & Dovey (1970) gives high apparent tryptophan contents for proteins having high tyrosine/tryptophan ratios. Correction for this interference by tyrosine can be achieved by plotting the ratio of observed to expected tryptophan content as a function of tyrosine/tryptophan ratio for proteins of known composition. The equation of the line is: [Formula: see text] Application of this correction to chicken ovoinhibitor, which contains 17 tyrosine residues per molecule, gave results that agree with tryptophan content determined by other methods.

Magnetic Circular Dichroism of Tryptophanyl Residues in Proteins

The magnetic circular dichroism (MCD) induced in the wavelength region of absorption by the aromatic chromophores of a number of proteins has been examined. The major contribution to the MCD is from the tryptophanyl chromophores and to a much lesser extent the tyrosyl chromophores. The magnetically induced CD of tryptophanyl residues is independent of the environment of the residue as indicated by the insensitivity of the MCD to protein denaturation. These characteristics make MCD a valuable analytical tool for the determination of tryptophan in proteins. Determinations of tryptophan content by this method on 9 proteins containing 0–6 tryptophanyl residues per molecule are reported. Certain features of MCD and natural CD are compared with particular attention to azurin and several mammalian carbonic anhydrases which have large natural ellipticity bands associated with the aromatic chromophores.

Magnetic circular dichroism studies. XII. The determination of tryptophan in proteins.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic circular dichroism studies. XII. Determination of tryptophan in proteinsCarl Djerassi, Guenter Barth, Ruth Records, Edward Bunnenberg, and Wolfgang VoelterCite this: J. Am. Chem. Soc. 1971, 93, 10, 2545–2547Publication Date (Print):May 1, 1971Publication History Published online1 May 2002Published inissue 1 May 1971https://doi.org/10.1021/ja00739a038RIGHTS & PERMISSIONSArticle Views66Altmetric-Citations41LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (339 KB) Get e-Alerts Get e-Alerts

Spectroscopic determination of tryptophan and tyrosine in proteins.

A rapid method for the determination of tryptophan in proteins is presented. It is based on ab- sorbance measurements at 288 and 280 mp of the protein dissolved in 6 M guanidine hydrochloride. Blocked tryptophanyl (N-acetyl-L-tryptophanamide) and tyrosyl (glycyl-L-tyrosylglycine) compounds were selected as C urrent methods of protein amino acid analysis do not give quantitative values for tryptophan and conse- quently the amino acid compositions, which are other- wise complete, fail to report tryptophan values. The principal reason for this situation is that the standard procedure of protein hydrolysis in strong acid results in the destruction of tryptophan (Hill, 1965). Therefore a second procedure is required to measure tryptophan. Alkaline hydrolysis is less destructive but does not give quantitative recoveries generally (Spies and Chambers, 1949). Enzymatic hydrolysis of proteins can give quanti- tative yields of tryptophan but this method may not be generally valid (Hill and Schmidt, 1962). The hydrolytic problem can be circumvented by meas- uring tryptophan in the intact protein. A chemical method has been developed which has not been exploited adequately (Spies and Chambers, 1948, 1949). On the other hand, considerable effort has been expended in developing absorption spectroscopic procedures to measure tryptophan and tyrosine in unhydrolyzed pro- teins. Holiday (1936) and Goodwin and Morton (1946) have measured the absorption of proteins in 0.1 M NaOH and computed their tryptophan and tyrosine contents based on comparison with the absorption of the two amino acids. A modification of these techniques has been presented by Bencze and Schmid (1957). The pre- ceding three methods do not give quantitative results. The behavior of the chromophores has not been nor- malized and the two models, i.e., tryptophan and tyro- sine, are not completely adequate. A procedure is sug- gested in this report which strongly reduces or elimi- nates these interactions, normalizes their absorption, and consequently permits a more precise analysis of tryptophan and tyrosine in proteins.

Notes sur les méthodes de dosage du tryptophane

1. A large part of the literature concerning the chemical determination of tryptophan and the explanation of the coloration given by tryptophan with aldehydes is reviewed. 2. The causes of the erroneous results obtained by using the p-dimethylamino-benzaldehyde method, in the presence of hydrochloric acid, have been ascertained. Contrarily to what some authors think, these erroneous results are not due to a lack of specificity of the method. 3. The results and the sensitivity of various methods are discussed. The most advantageous method for the determination of tryptophan in proteins seems to be at the present time,the method described by Spies and Chambers 62.

Chemical Determination of Tryptophan in Proteins

Chemical Determination of Tryptophan in Proteins