The structure basis of the poor fibrin specificity of urokinase (II)--The inhibition of urokinase A chain 149-157 on the fibrin stimulated activation of plasminogen by tissue type plasminogen activator.
In view of the similarity of the charge distribution between fibrin A alpha 148-161 and A chain 149-157 of urokinase, the latter might compete with fibrin A alpha 148-161 when single chain pro-urokinase is converted to double chain urokinase. To test this, the stretch of urokinase A chain 135-157 was separated from the low molecular weight urokinase, a competitive binding between this stretch and fibrin to tPA kringle-2 was shown by radio-binding assay. The inhibition of the stretch on the fibrin stimulated activation of plasminogen was demonstrated in the caseinolytic system. The synthesized novapeptide urokinase A chain 149-157 (R-peptide) showed a significant inhibition on the activation of plasminogen in the presence of fibrin. By contrasting finely with R-peptide, a synthesized novapeptide in which Arg154 and Arg156 were replaced by Asp (D-peptide) did not show any inhibition effect on the fibrin stimulated activation of plasminogen by tPA. These results suggest that the positively charged residues in the stretch 149-157 of urokinase are crucial for the inhibition of fibrin binding with the kringle domain of urokinase.
Song
A
A
Department of Biochemistry, Nanjing University, PRC.
Liu
J N
JN
Yu
R R
RR
Cui
D F
DF
Zhou
T M
TM
Cui
H R
HR
Zhu
D X
DX
D000595:Amino Acid Sequence; D002096:C-Peptide / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D005337:Fibrin / Q000494:pharmacology*; D005341:Fibrinolysin / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D010958:Plasminogen / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
D002096:C-Peptide; D004792:Enzyme Precursors; D010446:Peptide Fragments; D011994:Recombinant Proteins; C081048:urokinase A chain 149-157; D005337:Fibrin; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; C067551:saruplase