Purification, crystallization and properties of the d-xylose isomerase from Lactobacillus brevis
1968; Elsevier BV; Volume: 151; Issue: 3 Linguagem: Inglês
10.1016/0005-2744(68)90015-6
ISSN1878-1454
Autores Tópico(s)Enzyme Structure and Function
Resumo1.d-Xylose isomerase (d-xylose ketol-isomerase, EC 5.3.1.5) has been purified and crystallized from the extracts of d-xylose-grown cells of Lactobacillus brevis 2.The crystalline enzyme appears from its sedimentation pattern to be homogeneous. d-Lyxose is inert with respect to this enzyme. In the reverse reaction, xylose is the only product of d-xylulose, but d-lyxose is not detected in the reaction products of d-xylulose. 3.This enzyme catalyzes the isomerization of d-xylose, d-glucose and d-ribose. The optimum pH is identical for these substrates, 6.0–7.0, while the Michaelis constants are very different: 5·10−3 M for d-xylose, 0.92 M for d-glucose and 0.67 M for d-ribose. 4.This enzyme required manganese ions for its activity and the Michaelis constant was found to be 6.1·10−6 M.
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