Structural relationship between "glutamic acid" and "lysine" forms of human plasminogen and their interaction with the NH2-terminal activation peptide as studied by affinity chromatography.
Urokinase digestion of maleinated plasminogen results in cleavage of the single peptide bond Arg-68-Met-69, which is one of the bonds normally cleaved during the first step of the activation procedure. The inactive intermediate compound formed in this way was subjected to NH2-terminal amino acid sequence analysis, which clearly demonstrates the structural relationship between the forms of plasminogen with different NH2-terminal amino acids. It is thus shown that lysine-78 and valine-79 in the "glutamic acid" plasminogen actually are the NH2-terminal amino acids in "lysine" and "valine" plasminogen respectively. The forms with glutamic acid in NH2-terminal position are called plasminogen A, while all other forms lacking the NH2-terminal part of the molecule and which can be activated in a single step are called plasminogen B. By affinity chromatographic studies of the NH2-terminal activation peptide on insolubilized plasminogen B, it was demonstrated that this peptide has specific affinity for plasminogen B. It was also shown that this noncovalent interaction is broken by 6-aminohexanoic acid in two concentration. The tryptic heptapeptide (Ala-Phe-Gln-Tyr-His-Ser-Lys) which occupies the positions number 45 to 51 in the NH2-terminal activation peptide (as well as in the intact plasminogen molecule) is importance for the conformational state of the plasminogen molecule.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004789:Enzyme Activation; D005341:Fibrinolysin; D005971:Glutamates; D006801:Humans; D008239:Lysine; D008298:Maleates; D008970:Molecular Weight; D010958:Plasminogen / Q000032:analysis; D014568:Urokinase-Type Plasminogen Activator; D014633:Valine
D000596:Amino Acids; D005971:Glutamates; D008298:Maleates; D010958:Plasminogen; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D014633:Valine; D008239:Lysine