Sheldon P S, Keen J N, Bowles D J
Centre for Plant Biochemistry, University of Leeds, U.K.
Biochem J. 1996 Dec 15;320 ( Pt 3)(Pt 3):865-70. doi: 10.1042/bj3200865.
Post-translational processing of concanavalin A (Con A) is complex, involving deglycosylation, proteolytic cleavage on the carboxy group side of asparagine residues and formation of a peptide bond de novo. This has been studied with the 125I-labelled Con A glycoprotein precursor as a substrate for processing in vitro. Extracts of immature jackbean cotyledons and the commercially available purified preparation of asparaginylendo-peptidase were able to catalyse the above processes. The processing resulted in the conversion of the 33.5 kDa inactive glycoprotein precursor into an active lectin. Processing activity was maximal at approx. pH 5.5. Evidence to support processing at authentic sites was obtained by observation of the release of 125I at positions in the sequence where tyrosine residues were present.
伴刀豆球蛋白A（Con A）的翻译后加工过程很复杂，包括去糖基化、天冬酰胺残基羧基侧的蛋白水解切割以及新肽键的形成。这一过程已使用125I标记的Con A糖蛋白前体作为体外加工的底物进行了研究。未成熟刀豆子叶提取物和市售的纯化天冬酰胺内肽酶制剂能够催化上述过程。加工过程导致33.5 kDa的无活性糖蛋白前体转化为活性凝集素。加工活性在约pH 5.5时最大。通过观察序列中酪氨酸残基所在位置的125I释放，获得了支持在真实位点进行加工的证据。
