Gavilanes F G, Gavilanes J G, Municio A M
Int J Pept Protein Res. 1981 May;17(5):539-45. doi: 10.1111/j.1399-3011.1981.tb02026.x.
Fructose 1, 6-biphosphate aldolase from Ceratitis capitata is a tetramer of identical subunits with 34% alpha-helix, 22% beta structure and 44% of aperiodic order. Increase of urea concentration up to 4.0 M results in non-cooperative reversible dissociation of the enzyme. Sodium dodecylsulphate 0.06% (w/v) dissociates the tetramer cooperatively with retention of the helical content. Thermal denaturation was a non-reversible cooperative process with a midpoint for the transition at 55 degrees. Cysteine residues are involved in this process and 2-mercaptoethanol preserves partially the enzyme activity. The acidic dissociation of the enzyme is a non-reversible process in contrast to the reversible basic dissociation. Increase of ionic strength results in a more ordered secondary structure for the monomer after acidic dissociation.
来自地中海实蝇的1,6-二磷酸果糖醛缩酶是由相同亚基组成的四聚体，其中α-螺旋占34%，β-结构占22%，无规排列占44%。尿素浓度增加至4.0 M会导致该酶发生非协同可逆解离。0.06%（w/v）的十二烷基硫酸钠会使四聚体协同解离，同时保留螺旋结构含量。热变性是一个不可逆的协同过程，转变中点温度为55℃。半胱氨酸残基参与了这一过程，2-巯基乙醇可部分保留酶活性。与可逆的碱解离相反，该酶的酸解离是一个不可逆过程。离子强度增加会使酸解离后的单体二级结构更加有序。
