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Acyl-enzyme complexes between tissue-type plasminogen activator and neuroserpin are short-lived in vitro. J Biol Chem 2002 Dec 06;277(49):46852-7

Date

09/14/2002

Pubmed ID

12228252

DOI

10.1074/jbc.M207740200

Scopus ID

2-s2.0-0345829928 (requires institutional sign-in at Scopus site)   56 Citations

Abstract

The serine protease tissue-type plasminogen activator (t-PA) initiates the fibrinolytic protease cascade and plays a significant role in motor learning, memory, and neuronal cell death induced by excitotoxin and ischemia. In the fibrinolytic system, the serpin PAI-1 negatively regulates the enzymatic activity of both single-chain and two-chain t-PA (sct-PA and tct-PA). In the central nervous system, neuroserpin (NSP) is a serpin thought to regulate t-PA enzymatic activity. We report that although both sct-PA and tct-PA rapidly form acyl-enzyme complexes with NSP in vitro, the interactions are short-lived, rapidly progressing to complete cleavage of NSP and regeneration of fully active enzyme. All NSP molecules appear to transit through the detectable acyl-enzyme intermediate and progress to completion of cleavage; no subpopulation that functions as a pure substrate was detected. Likewise, all molecules were reactive, with no evidence of a latent subpopulation. The interactions between NSP and t-PA were distinct from those between plasmin and NSP, wherein the same peptide bond was cleaved but there was no evidence of a detectable plasmin-NSP acyl-enzyme complex. The interactions between t-PA and NSP contrast with the formation of long-lived, physiologically irreversible acyl-enzyme complexes between t-PA and PAI-1, suggesting that the physiologic effect of t-PA-NSP interactions may be more complex than previously thought.

Author List

Barker-Carlson K, Lawrence DA, Schwartz BS

Author

Karen-Sue B. Carlson MD, PhD Associate Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Binding Sites
Blotting, Western
DNA, Complementary
Dose-Response Relationship, Drug
Electrophoresis, Polyacrylamide Gel
Fibrinolysin
Humans
Neuropeptides
Peptides
Protein Binding
RNA
Reproducibility of Results
Reverse Transcriptase Polymerase Chain Reaction
Serpins
Substrate Specificity
Temperature
Time Factors
Tissue Plasminogen Activator