[单价阳离子对中间柠檬酸杆菌酪氨酸-苯酚裂解酶催化及光谱性质的影响]

[Effect of monovalent cations on the catalytic and spectral properties of tyrosine-phenol-lyase from Citrobacter intermedius].

作者信息

Miagkikh I V, Demidkina T V

出版信息

Mol Biol (Mosk). 1985 May-Jun;19(3):671-8.

Abstract

The action of monovalent cations Li+, Na+, K+, Rb+, Cs+, NH4+ on catalytic and physico-chemical properties of bacterial tyrosine--phenol-lyase was investigated. It was shown that K+, Rb+, Cs+, NH4+ were the noncompetitive activators of the enzyme, Na+ was an inhibitor, Li+ did not influence the catalytic activity. The values of KA and Vmax were determined for the activators in the reaction of alpha, beta-elimination of L-tyrosine. Monovalent cations affect the absorption and CD spectra of the enzyme and its complex with the quasi-substrate--L-alanine. It was suggested that an activation of tyrosine phenollyase by monovalent cations was connected with the increase of the active protonated form of the holoenzyme (lambda max 420 mm) induced by the cations-activators.

摘要

研究了单价阳离子Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄⁺对细菌酪氨酸 - 酚裂解酶催化及物理化学性质的影响。结果表明，K⁺、Rb⁺、Cs⁺、NH₄⁺是该酶的非竞争性激活剂，Na⁺是抑制剂，Li⁺不影响催化活性。测定了L - 酪氨酸α,β - 消除反应中激活剂的KA和Vmax值。单价阳离子影响酶及其与准底物 - L - 丙氨酸复合物的吸收光谱和圆二色光谱。有人提出，单价阳离子对酪氨酸酚裂解酶的激活与激活剂阳离子诱导的全酶活性质子化形式（λmax 420nm）增加有关。