{"title":"A single protein research integrated advanced biochemistry laboratory course; spectroscopic determination of tyrosyl side chain pKa","authors":"Brian N. Blanchette, Bal Ram Singh","doi":"10.1016/S0307-4412(99)00127-2","DOIUrl":null,"url":null,"abstract":"<div><p>The unique bio-analytical properties of the amino acid tyrosine (Tyr) are the focus of this experiment from the research oriented biochemistry laboratory course at our university. In the present study p<em>K</em><sub>a<sub>1</sub></sub>, p<em>K</em><sub>a<sub>2</sub></sub>, and p<em>K</em><sub>a<sub>3</sub></sub> values for free Tyr were estimated to be 2.30, 9.40, and 9.97, respectively, when free Tyr was titrated with 1<!--> <!-->mM NaOH and 1<!--> <!-->mM HCl using a pH meter. Spectrophotometric analysis of the phenolic side chain p<em>K</em><sub>a<sub>3</sub></sub> revealed a value of 10.14, which was consistent with the p<em>K</em><sub>a</sub><em>s</em> estimated from the pH meter. The results from this experiment will allow students to compare the free Tyr properties with those present in a protein.</p></div>","PeriodicalId":80258,"journal":{"name":"Biochemical education","volume":"28 2","pages":"Pages 107-109"},"PeriodicalIF":0.0000,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0307-4412(99)00127-2","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochemical education","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0307441299001272","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The unique bio-analytical properties of the amino acid tyrosine (Tyr) are the focus of this experiment from the research oriented biochemistry laboratory course at our university. In the present study pKa1, pKa2, and pKa3 values for free Tyr were estimated to be 2.30, 9.40, and 9.97, respectively, when free Tyr was titrated with 1 mM NaOH and 1 mM HCl using a pH meter. Spectrophotometric analysis of the phenolic side chain pKa3 revealed a value of 10.14, which was consistent with the pKas estimated from the pH meter. The results from this experiment will allow students to compare the free Tyr properties with those present in a protein.