Bergman L W, Kuehl W M
Biochemistry. 1978 Nov 28;17(24):5174-80. doi: 10.1021/bi00617a017.
The initial glycosylation of MPC 11 gamma 2b heavy chains occurs quantitatively in vivo when the nascent heavy chains reach a size of approximately 38 000 daltons. Nonglycosylated, completed MPC 11 heavy chains cannot be glycosylated in these cells. Other classes of mouse heavy chains (i.e., mu, alpha, and gamma 1) also appear to be glycosylated as nascent chains; nonglycosylated, completed heavy chains cannot be glycosylated by the cell in any of these cases. In contrast, variant MPC 11 cells synthesizing a heavy chain with a carboxy-terminal deletion appear to glycosylate some heavy chains prior to chain completion and some heavy chains after chain completion and release from the polysomes. Similar to the variant MPC 11 cells, MOPC 46B cells (which synthesize a kappa light chain containing an oligosaccharide attached to an asparagine located 28 residues from the amino terminus) glycosylate the majority of light chains after prior to chain completion but also some light chains after chain completion and release from the polysomes. In addition, it appears that, although completed MOPC 46B light chains can be glycosylated if they are present in a monomeric form, they cannot be glycosylated if they are present in a covalent dimeric form.
当新生重链达到约38000道尔顿大小时，MPC 11γ2b重链的初始糖基化在体内定量发生。未糖基化的完整MPC 11重链在这些细胞中不能被糖基化。其他类别的小鼠重链（即μ、α和γ1）似乎也作为新生链被糖基化；在任何这些情况下，未糖基化的完整重链都不能被细胞糖基化。相比之下，合成具有羧基末端缺失的重链的变异MPC 11细胞似乎在链完成之前糖基化一些重链，在链完成并从多核糖体释放后糖基化一些重链。与变异MPC 11细胞类似，MOPC 46B细胞（合成一种κ轻链，该轻链含有一个连接到距氨基末端28个残基处的天冬酰胺上的寡糖）在链完成之前糖基化大多数轻链，但在链完成并从多核糖体释放后也糖基化一些轻链。此外，似乎尽管完整的MOPC 46B轻链以单体形式存在时可以被糖基化，但以共价二聚体形式存在时则不能被糖基化。
