Bond J S, Barrett A J
Biochem J. 1980 Jul 1;189(1):17-25. doi: 10.1042/bj1890017.
The mechanism of degradation of fructose-1,6-bisphosphate aldolase from rabbit muscle by the lysosomal proteinase cathepsin B was determined. Treatment of aldolase with cathepsin B destroys up to 90% of activity with fructose 1,6-bisphosphate as substrate, but activity with fructose 1-phosphate is slightly increased. Cathepsin L, another lysosomal thiol proteinase, and papain are also potent inactivators of aldolase, whereas inactivation is not caused by cathepsins D or H even at high concentrations, or by cathepsin B inhibited by leupeptin or iodoacetate. The cathepsin-B-treated aldolase shows no detectable change in subunit molecular weight, oligomer molecular weight or subunit interactions. Cathepsin B cleaves dipeptides from the C-terminus of th aldolase subunits. Four dipeptides are released sequentially: Ala-Tyr, Asn-His, Ile-Ser and Leu-Phe, and a maximum of five additional dipeptides may be released. There are indications that this peptidyldipeptidase activity of cathepsin B may be an important aspect of its action on protein substrates generally.
已确定溶酶体蛋白酶组织蛋白酶B对兔肌肉中果糖-1,6-二磷酸醛缩酶的降解机制。用组织蛋白酶B处理醛缩酶会使以果糖1,6-二磷酸为底物时的活性丧失高达90%，但以果糖1-磷酸为底物时的活性略有增加。另一种溶酶体巯基蛋白酶组织蛋白酶L和木瓜蛋白酶也是醛缩酶的有效失活剂，而即使在高浓度下，组织蛋白酶D或H以及被亮抑酶肽或碘乙酸抑制的组织蛋白酶B都不会导致醛缩酶失活。经组织蛋白酶B处理的醛缩酶在亚基分子量、寡聚体分子量或亚基相互作用方面未显示出可检测到的变化。组织蛋白酶B从醛缩酶亚基的C末端切割二肽。依次释放出四种二肽：丙氨酸-酪氨酸、天冬酰胺-组氨酸、异亮氨酸-丝氨酸和亮氨酸-苯丙氨酸，并且最多可能再释放出五种二肽。有迹象表明，组织蛋白酶B的这种肽基二肽酶活性可能是其对一般蛋白质底物作用的一个重要方面。
