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Kinetic Method Analysis of the Effect of Halogenation on Relative Proton Affinity of Tyrosine
Author(s) -
Gannamani Bharathi,
Shin JoongWon
Publication year - 2016
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201500208
Subject(s) - chemistry , electronegativity , polarizability , halogenation , molecule , tyrosine , affinities , kinetic energy , proton affinity , computational chemistry , isotropy , stereochemistry , organic chemistry , ion , biochemistry , physics , quantum mechanics , protonation
Relative proton affinities ( PA s) of tyrosine, 3‐chlorotyrosine, and 3‐iodotyrosine were obtained using the kinetic method approach. The measured mean values are 922.5, 912.9, and 917.9 kJ/mol, respectively, with ± 0.1 kJ/mol standard deviation, indicating that halogenation of tyrosine decreases its PA . In general, PA of a molecule increases as its isotropic polarizability increases, but no such correlation has been found for the three molecules investigated in this study. Our findings show that PA decreases with increasing electronegativity of the modifying atom for a halogenated molecule, further supporting computational results of previous work [5].