Isolation and characterization of native and lower molecular weight forms of sheep plasminogen.
Two major forms of native sheep plasminogen (SPg-a) have been isolated from plasma by affinity chromatography. These forms differ in molecular weight, charge characteristics, affinity for epsilon-aminocaproic acid (epsilon-Ahx), and carbohydrate content. Upon treatment of SPg-a with plasmin, lower molecular weight  plasminogens can be isolated. A plasminogen (SPg-b) of molecular weight approximately 8,000 less than native plasminogen is rapidly produced when either major plasminogen form is treated with plasmin. The molecular weight differences found in the major SPg-a forms are retained in the SPg-b forms, derived from each SPg-a. Upon protracted treatment of either major form of SPg-a or SPg-b with plasmin, a plasminogen (SPg-c) or molecular weight approximately 32,000 less than SPg-b is produced. A single peptide (P) is also produced in this step. The SPg-c species produced from each original SPg-a major form possess essentially the same molecular weights and carbohydrate compositions; but the P cleaved retains the molecular weight and carbohydrate differences found in each major SPg-a or SPg-b form. A large decrease in the S20,w of SPg-a is observed upon the binding of epsilon-Ahx to this protein. A much smaller alteration in the S20,w of SPg-b and SPg-c is observed upon binding of epsilon-Ahx to these proteins.
D000596:Amino Acids / Q000032:analysis; D015119:Aminocaproic Acid; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D004789:Enzyme Activation; D005341:Fibrinolysin; D046911:Macromolecular Substances; D008970:Molecular Weight; D010958:Plasminogen / Q000302:isolation & purification; D012756:Sheep
D000596:Amino Acids; D002241:Carbohydrates; D046911:Macromolecular Substances; D010958:Plasminogen; D005341:Fibrinolysin; D015119:Aminocaproic Acid