Amino acid sequence analysis of the asparagine-288 region of the carbohydrate variants of human plasminogen.

The amino acid sequences of the two major carbohydrate variants in the region of Asn288 have been determined. A peptide isolated from plasminogen variant 1, which contains a complex-type Asn288-linked oligosaccharide, was found to possess the amino acid sequence-Ser280-Ala-Gln-Thr-Pro-His-Thr-His-Asn(CHO)-Arg-Thr290-Pro-Glu-, in agreement with the previously published sequence [Sottrup-Jensen, L., Claeys, H., Zajdel, M., Petersen, T. E., & Magnusson, S. (1978) in Progress in Chemical Fibrinolysis and Thrombolysis (Davidson, J. F., Rowan, R. M., Samama, M. M., & Desnoyers, P. C., Eds.) Vol. 3, pp 191-209, Raven Press, New York]. A similar peptide isolated from plasminogen variant 2 did not contain oligosaccharide but possessed an amino acid sequence identical with the corresponding variant 1 peptide. Thus, the basis for the lack of the complex-type oligosaccharide in human plasminogen variant 2 does not reside in substitution of essential amino acid residues in the region of the Asn288-linked glycosylation site.