Airas R K
Department of Biochemistry, University of Turku, Finland.
Biochem J. 1988 Mar 1;250(2):447-51. doi: 10.1042/bj2500447.
A pseudomonad was separated having a pantothenase that produced beta-alanine and pantoic acid. The pantothenase from an old strain, Pseudomonas fluorescens UK-1, was shown to produce beta-alanine and pantoyl lactone. The pantoic acid-producing pantothenase was characterized and compared with the pantothenase from the strain UK-1. The Mr was 240,000; it apparently consists of four subunits. The Km value for pantothenate is 3 mM. The enzymic activity is affected by an ionizable group of pK 8.4, the enzyme is active at higher pH, and V but not Km is affected by pH. This pantothenase is not inhibited by di-isopropyl phosphorofluoridate or phenylmethanesulphonyl fluoride, unlike the enzyme from the strain UK-1. Both pantothenases are inhibited by m-aminophenylboronic acid, oxalate, oxaloacetate and Cl- ions. The pantoic acid-producing pantothenase is inhibited also by SO4(2-) ions. The strong inhibitions by many compounds make this pantothenase unsuitable for the assay of pantothenic acid.
分离出了一种具有泛解酸酶的假单胞菌，该酶可产生β-丙氨酸和泛解酸。来自旧菌株荧光假单胞菌UK-1的泛解酸酶被证明可产生β-丙氨酸和泛酰内酯。对产生泛解酸的泛解酸酶进行了表征，并与菌株UK-1的泛解酸酶进行了比较。其相对分子质量为240,000；它显然由四个亚基组成。泛酸盐的米氏常数为3 mM。酶活性受pK 8.4的可电离基团影响，该酶在较高pH值下有活性，并且V受pH影响但Km不受影响。与菌株UK-1的酶不同，这种泛解酸酶不受二异丙基氟磷酸酯或苯甲基磺酰氟的抑制。两种泛解酸酶都受间氨基苯硼酸、草酸盐、草酰乙酸盐和Cl-离子的抑制。产生泛解酸的泛解酸酶也受SO4(2-)离子的抑制。许多化合物的强烈抑制作用使得这种泛解酸酶不适用于泛酸的测定。
