Gonzy-Treboul G, Chambert R, Dedonder R
Biochimie. 1975;57(1):17-28. doi: 10.1016/s0300-9084(75)80105-2.
To give some support to researchs presently in progress in this institute, on the sequence elucidation and the X-Ray pattern of the levansucrase of B. subtilis, some physical and chemical properties of this enzyme were carefully reexaminated. The results explicit and on some points rectify previous reports from this laboratory. The molecular weight was measured by three different methods: sedimentation equilibrium, SDS-gel electrophoresis, gel filtration. They give an average value of 54000 g. From this molecular weight and the value of the Stokes' radius, an estimate of the frictional ratio f/fo was calculated. These results provide some knowledge about the size and the shape of the molecule. They are consistent with the electronic microscopy observations obtained elsewhere. The amino acid composition was determined from the acid hydrolysate. The nature of the sulfur containing aminoacid was established by analysis of (35-S)-labelled levansucrase : neither cysteine nor cystine were found in the molecule. The methionine residues appear essentially under unoxidized form. One terminal residue was characterized by the dansylation method using (14-C)-labelled dansyl chloride. An explanation of the affinity of the levansucrase on hydroxyapatite was attempted.
为了支持本研究所目前正在进行的关于枯草芽孢杆菌蔗糖转化酶的序列解析和X射线图谱的研究，我们对该酶的一些物理和化学性质进行了仔细的重新研究。结果明确，并且在某些方面纠正了本实验室以前的报告。分子量通过三种不同方法测定：沉降平衡、SDS-凝胶电泳、凝胶过滤。它们给出的平均值为54000 g。根据这个分子量和斯托克斯半径的值，计算了摩擦比f/fo的估计值。这些结果提供了关于分子大小和形状的一些知识。它们与在其他地方获得的电子显微镜观察结果一致。氨基酸组成由酸水解产物测定。通过对（35-S）标记的蔗糖转化酶的分析确定了含硫氨基酸的性质：分子中未发现半胱氨酸和胱氨酸。甲硫氨酸残基基本上以未氧化形式出现。使用（14-C）标记的丹磺酰氯通过丹磺酰化方法表征了一个末端残基。我们尝试对蔗糖转化酶对羟基磷灰石的亲和力作出解释。
