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PubMed · 6179934

Phosphotyrosine in proteins. Stability and quantification.

T M Martensen
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Abstract

The acid and base stability of the phosphoryl bond of phosphotyrosine (Tyr-P) was studied using conditions for rapid and complete hydrolysis of protein peptide bonds. A method was developed for the quantification of Tyr-P in proteins using rapid base hydrolysis and an amino acid analyzer equipped with a fluorometric detection system. The recovery of [32P]Tyr-P from base digests of radiolabeled samples of phosphotyrosyl glutamine synthetase, transforming protein of Rous sarcoma virus, casein, and rabbit anti-sarcoma IgG was 80 +/- 2%. Phosphotyrosine could not be detected in several commercial histone samples, but Tyr-P was detected in phosvitin samples. The putative Tyr-P from the phosvitin hydrolysate was separated from normal amino acids by Dowex 50-H+ chromatography. Treatment of the partially purified Tyr-P with bacterial alkaline phosphatase produced tyrosine in near equivalent quantities to the measured level of Tyr-P. These results show that basic hydrolysis of phosphotyrosyl proteins yields Tyr-P in constant and good yields which can be quantified in amounts greater than or equal to 100 pmol or radiochemically detected in smaller amounts with an amino acid analyzer.

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Antibodies, NeoplasmCaseinsDrug StabilityGlutamate-Ammonia LigaseHydrogen-Ion ConcentrationHydrolysisImmunoglobulin GPeptidesPhosphotyrosinePhosvitinProteinsSarcomaTransforming Growth FactorsTyrosineJournal ArticleResearch Support, Non-U.S. Gov't

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T M Martensen. 1982-08-25. Phosphotyrosine in proteins. Stability and quantification.. https://pubmed.ncbi.nlm.nih.gov/6179934/

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