Hubert E, Ojeda A, Reyes A, Slebe J C
Arch Biochem Biophys. 1986 Nov 1;250(2):336-44. doi: 10.1016/0003-9861(86)90735-6.
The specific chemical modification by sodium cyanate of highly reactive cysteine residues at pH 7.5 in pig kidney fructose 1,6-bisphosphatase results in the reversible loss of activation of the enzyme by monovalent cations. No loss of activation by potassium ions occurs when modification is carried out in the presence of fructose 2,6-bisphosphate. The effect of Mg2+ on native and cyanate-modified enzyme activities implicates the above cysteine residue as being directly linked to the inhibition by both the divalent cation and fructose 2,6-bisphosphate. Incorporation of [14C]cyanate to the enzyme shows that the blockage of two reactive residues per tetramer is sufficient to eliminate the activation of the enzyme by K+.
在pH 7.5条件下，用氰酸钠对猪肾果糖1,6-二磷酸酶中高反应性半胱氨酸残基进行特异性化学修饰，会导致该酶被单价阳离子激活的能力可逆丧失。当在果糖2,6-二磷酸存在的情况下进行修饰时，钾离子不会导致激活能力丧失。镁离子对天然酶和经氰酸盐修饰的酶活性的影响表明，上述半胱氨酸残基与二价阳离子和果糖2,6-二磷酸的抑制作用直接相关。将[14C]氰酸盐掺入该酶表明，每个四聚体阻断两个反应性残基就足以消除钾离子对该酶的激活作用。
