二酪氨酸的荧光特性：与硼酸和硼酸根离子形成的复合物

Fluorometric characterization of dityrosine: complex formation with boric acid and borate ion.

作者信息

Malencik D A, Anderson S R

机构信息

Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331-6503.

出版信息

Biochem Biophys Res Commun. 1991 Jul 15;178(1):60-7. doi: 10.1016/0006-291x(91)91779-c.

DOI:10.1016/0006-291x(91)91779-c

PMID:2069580

Abstract

Borate/boric acid solutions have distinctive effects on the absorption and fluorescence emission spectra of dityrosine. In the presence of excess borate/boric acid, the fluorescence emission maximum of the singly ionized dityrosine chromophore shifts from 407 nm (quantum yield = 0.80) to 374 nm (quantum yield = 0.14). Fluorescence measurements performed as a function of pH and concentration are consistent with a 1:1 complex which may dissociate to either boric acid and singly ionized dityrosine (K1 = 17 mM) or to monoborate ion and unionized dityrosine (K2 = 0.10 mM). As a consequence of the pKa values characteristic of dityrosine and boric acid, complex formation is maximal near pH 8. 2,2'-Dihydroxy-biphenyl shows similar interactions. The fluorescence of dityrosyl calmodulin (0 Ca2+) also responds to the addition of boric acid, giving K1 = 42 mM and K2 = 2 mM. Singly ionized dityrosine produced through dissociation occurring in the excited state does not interact with boric acid.

摘要

硼酸盐/硼酸溶液对二酪氨酸的吸收光谱和荧光发射光谱有独特的影响。在过量硼酸盐/硼酸存在的情况下，单离子化二酪氨酸发色团的最大荧光发射波长从407 nm（量子产率 = 0.80）移至374 nm（量子产率 = 0.14）。作为pH和浓度函数进行的荧光测量结果与1:1络合物相符，该络合物可能解离为硼酸和单离子化二酪氨酸（K1 = 17 mM）或单硼酸盐离子和未离子化二酪氨酸（K2 = 0.10 mM）。由于二酪氨酸和硼酸的特征pKa值，在pH 8附近络合物形成达到最大值。2,2'-二羟基联苯表现出类似的相互作用。二酪氨酸钙调蛋白（0 Ca2+）的荧光也对硼酸的添加有响应，得到K1 = 42 mM和K2 = 2 mM。通过激发态解离产生的单离子化二酪氨酸不与硼酸相互作用。