Primary structure of human alpha 2-macroglobulin. II. Primary structure of eight CNBr fragments located in the NH2-terminal half of alpha 2-macroglobulin, accounting for 603 amino acid residues.

Abstract

The amino acid sequence has been determined for eight medium-sized CNBr fragments from the NH2-terminal part of human alpha 2-macroglobulin. The fragments are: CB2 (10-78), CB5 (129-223), CB6 (224-295), CB7 (296-392), CB8 (393-441), CB11 (498-584), CB12 (585-643), and CB17 (691-775). These fragments account for 603 of the 1451 residues of the subunits of alpha 2-macroglobulin. CB2 contains two glucosamine-based carbohydrate groups attached to Asn-23 and Asn-38, and one internal disulfide bridge connecting Cys-16 with Cys-54. CB6 contains one glucosamine-based carbohydrate group attached to Asn-1 and two internal disulfide bridges (Cys-5 bound to Cys-53 and Cys-23 bound to Cys-41, respectively); Cys-32 is bound to Cys-16 in CB8. CB7 contains two glucosamine-based carbohydrate groups attached to Asn-78 and Asn-92, CB8 contains 1 Cys residue (Cys-16), bridged to Cys-32 of CB6. CB11 contains 1 Cys residue (Cys-75), bridged to Cys-58 of CB17. CB12 contains 1 Cys residue (Cys-35), bridged to Cys-1 of CB15. CB17 contains 1 Cys residue (Cys-58), bound to Cys-75 of CB11.