Tissue plasminogen activator: peptide analyses confirm an indirectly derived amino acid sequence, identify the active site serine residue, establish glycosylation sites, and localize variant differences

Biochemistry ◽  
1984 ◽  
Vol 23 (16) ◽  
pp. 3701-3707 ◽  
Author(s):  
Gunnar Pohl ◽  
Margareta Kaellstroem ◽  
Nils Bergsdorf ◽  
Per Wallen ◽  
Hans Joernvall
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Active Site ◽  
Serine Residue ◽  
Glycosylation Sites ◽  
Tissue Plasminogen

scholarly journals Tissue plasminogen activator is a ligand of cation-independent mannose 6-phosphate receptor and consists of glycoforms that contain mannose 6-phosphate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James J. Miller ◽  
Richard N. Bohnsack ◽  
Linda J. Olson ◽  
Mayumi Ishihara ◽  
Kazuhiro Aoki ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Dependent Manner ◽  
Plasminogen Activation ◽  
Urokinase Plasminogen Activator Receptor ◽  
Plasminogen Activation System ◽  
Extracellular Region ◽  
Glycosylation Sites ◽  
Tissue Plasminogen ◽  
Mannose 6 Phosphate

AbstractPlasmin is the key enzyme in fibrinolysis. Upon interaction with plasminogen activators, the zymogen plasminogen is converted to active plasmin. Some studies indicate plasminogen activation is regulated by cation-independent mannose 6-phosphate receptor (CI-MPR), a protein that facilitates lysosomal enzyme trafficking and insulin-like growth factor 2 downregulation. Plasminogen regulation may be accomplished by CI-MPR binding to plasminogen or urokinase plasminogen activator receptor. We asked whether other members of the plasminogen activation system, such as tissue plasminogen activator (tPA), also interact with CI-MPR. Because tPA is a glycoprotein with three N-linked glycosylation sites, we hypothesized that tPA contains mannose 6-phosphate (M6P) and binds CI-MPR in a M6P-dependent manner. Using surface plasmon resonance, we found that two sources of tPA bound the extracellular region of human and bovine CI-MPR with low-mid nanomolar affinities. Binding was partially inhibited with phosphatase treatment or M6P. Subsequent studies revealed that the five N-terminal domains of CI-MPR were sufficient for tPA binding, and this interaction was also partially mediated by M6P. The three glycosylation sites of tPA were analyzed by mass spectrometry, and glycoforms containing M6P and M6P-N-acetylglucosamine were identified at position N448 of tPA. In summary, we found that tPA contains M6P and is a CI-MPR ligand.

scholarly journals The mechanism of the reaction between human plasminogen-activator inhibitor 1 and tissue plasminogen activator

1990 ◽  
Vol 265 (1) ◽  
pp. 109-113 ◽  
Author(s):  
T L Lindahl ◽  
P I Ohlsson ◽  
B Wiman
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Peptide Bond ◽  
Plasminogen Activator Inhibitor 1 ◽  
Sds Page ◽  
Tissue Plasminogen ◽  
Activator Inhibitor ◽  
Pai 1

The structural events taking place during the reaction between PAI-1 (plasminogen-activator inhibitor 1) and the plasminogen activators sc-tPA (single-chain tissue plasminogen activator) and tc-tPA (two-chain tissue plasminogen activator) were studied. Complexes were formed by mixing sc-tPA or tc-tPA with PAI-1 in slight excess (on an activity basis). The complexes were purified from excess PAI-1 by affinity chromatography on fibrin-Sepharose. Examination of the purified complexes by SDS/polyacrylamide-gel electrophoresis (SDS/PAGE) and N-terminal amino acid sequence analysis demonstrated that a stoichiometric 1:1 complex is formed between PAI-1 and both forms of tPA. Data obtained from both complexes revealed the amino acid sequences of the parent molecules and, in addition, a new sequence: Met-Ala-Pro-Glu-Glu-. This sequence is found in the C-terminal portion of the intact PAI-1 molecule and thus locates the reactive centre of PAI-1 to Arg346-Met347. The proteolytic activity of sc-tPA is demonstrated by its capacity to cleave the ‘bait’ peptide bond in PAI-1. The complexes were inactive and dissociated slowly at physiological pH and ionic strength, but rapidly in aq. NH3 (0.1 mol/l). Amidolytic tPA activity was generated on dissociation of the complexes, corresponding to 0.4 mol of tPA/mol of complex. SDS/PAGE of the dissociated complexes indicated a small decrease in the molecular mass of PAI-1, in agreement with proteolytic cleavage of the ‘bait’ peptide bond during complex-formation.

scholarly journals Catabolism of human tissue plasminogen activator in mice

Blood ◽  
1985 ◽  
Vol 65 (3) ◽  
pp. 539-544 ◽  
Author(s):  
HE Fuchs ◽  
H Jr Berger ◽  
SV Pizzo
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Active Site ◽  
Human Tissue ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Organ Distribution ◽  
Tissue Plasminogen ◽  
Iodine 125 ◽  
Distribution Studies

The catabolism of human tissue plasminogen activator (t-PA) was studied in mice. The clearance of t-PA labeled with iodine 125 was rapid (t1/2). The clearance of phenylmethylsulfonyl-125I-t-PA, which is active site-inhibited, was identical to the active enzyme. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that the vast majority of 125I-t-PA injected into the circulation was present as free enzyme and not in a complex with inhibitors. The clearance of 125I-t-PA was unaltered by large molar excesses of several ligands of known clearance specificities, including macroalbumin, asialoorosomucoid, and diisopropylphosphorylthrombin and was also not altered in the presence of a 1,000-fold molar excess of unlabeled t-PA. Organ distribution studies demonstrated that the early rapid clearance of 125I-t-PA occurred in hepatocytes, followed by a later renal phase of clearance. The clearance of 125I-urokinase (UK) also was studied and was very similar in all aspects to the clearance of 125I-t-PA. These results suggest that both t-PA and UK are cleared from the circulation by unique nonsaturable processes localized in the liver that are independent of the proteinase active site.

PURIFICATION AND CHARACTERIZATION OF TISSUE PLASMINOGEN ACTIVATOR PRODUCED BY IMR-90 CELLS

1987 ◽  
Author(s):  
T Morinaga ◽  
Y Itagaki ◽  
A Suzuki ◽  
H Yasuda ◽  
K Higashio
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Clot Lysis ◽  
Nucleotide Sequence Analysis ◽  
Filtration Method ◽  
Tissue Plasminogen

Tissue plasminogen activator ( t-PA ) produced by IMR-90 ( human embryonic fibroblast ) cells cultured in the serum-free medium ( DMEM ) containing 1% proteos^e peptone and 1.6 - 3.6mM CaCl2 was purified by the procedure consisted of ultrafiltration, immunoadsorpt ion chromatography, HPLC and lysine-Sepharose chromatography. The yield of t-PA from the culture broth was approximately 47%. The purified t-PA migrated as a single band on SDS-polyacrylamide gels. The molecular weight of the t-PA was estimated to be 66,000 by SDS-polyacrylamide gel electrophoresis and 69,000 by gel filtration method. Purified t-PA had a specific activity of 36 × 104 IU/mg protein by fiblin plate method or 54 - 56 X 104 IU/mg protein by clot lysis method using t-PA obtained from WHO as a standard. The amino acid composition of fibroblast t-PA was very similar to those of melanoma t-PA and uterine t-PA. Isoelectric point of fibroblast t-PA ranged from 5-7 to 8.2. The t-PA had twice as much affinity for fiblin as did high molecular weight urokinase ( UK ). Both t-PA and UK had optimum temperature at 41°C and optimum pH between 8.0 - 9.0. The polyclonal and monoclonal antibodies raised against t-PA quenched t-PA activity but had no effect on UK activity. The inhibitors of serine proteases, difluorophos-phate and gabexate mesilate, strongly inhibited the activities of fibroblast t-PA and UK. The nucleotide sequence analysis of the t-PA cDNA isolated from the cDNA library prepared from IMR-90 mRNA revealed the nucleotide changes at two positions in the coding region as compared to that of melanoma t-PA cDNA. Neither of the changes replaced the coded amino acid. The N-terminal amino acid of fibroblast t-PA was determined to be valine, indicatig the structural similarity of fibroblast t-PA to uterine t-PA.

scholarly journals Binding of tissue plasminogen activator to human endothelial cells. Importance of the B-chain as a ligand

1992 ◽  
Vol 287 (2) ◽  
pp. 407-413 ◽  
Author(s):  
X F Cheng ◽  
O Bäck ◽  
T K Nilsson ◽  
E Nylander Lundqvist ◽  
G Pohl ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Active Site ◽  
Binding Sites ◽  
Human Umbilical Cord ◽  
Cultured Endothelial Cells ◽  
Tissue Plasminogen ◽  
A Chain ◽  
Pai 1

The aim of the present study was to investigate the binding of tissue plasminogen activator (tPA) to cultured endothelial cells and to characterize binding structures present in the cultures. Studies on the binding of 125I-tPA to cultured endothelial cells from human umbilical-cord veins (HUVEC) indicated that the number of sites for specific binding of tPA is 8 x 10(5) per cell. Treatment with an excess of antibodies against plasminogen-activator inhibitor type 1 (PAI-1) caused an 80% decrease in the binding, leaving about 1.6 x 10(5) unoccupied binding sites per cell, which appeared to be different from PAI-1. About 1.9 x 10(5) binding sites/cell for tPA were found on the surface of HUVEC that had been detached from the matrix. This indicates that only minor amounts of PAI-1 occur on the surface of the cells. In addition, immunocytochemical analysis showed that PAI-1 antigen is present almost exclusively in the cytoplasm but was not observed on the surface of the cells, whereas tPA antigen is abundant on the plasma membrane of tPA-treated cells as well as intracellularly. Competition studies using unlabelled compounds showed that native tPA and tPA B-chain (the proteinase domain), as well as the inactive derivatives, B-chain inactivated with D-Phe-Pro-Arg-chloromethane and tPA-PAI-1 complex, caused a considerable quenching of the binding of 125I-tPA to HUVEC, whereas the isolated A-chain had no demonstrable effect. Two components (apparent molecular masses 38 kDa and 56 kDa) reacting with tPA but lacking PAI-1 antigen determinants were identified. Thus the data suggest that tPA binds to HUVEC by two principally different mechanisms. One is mediated by PAI-1, which binds and inactivates tPA with a functional active site. The other binding is achieved by components which react with sites on the activator molecule other than structures of the A-chain or the active site.

scholarly journals Catabolism of human tissue plasminogen activator in mice

Blood ◽  
1985 ◽  
Vol 65 (3) ◽  
pp. 539-544 ◽  
Author(s):  
HE Fuchs ◽  
H Jr Berger ◽  
SV Pizzo
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Active Site ◽  
Human Tissue ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Organ Distribution ◽  
Tissue Plasminogen ◽  
Iodine 125 ◽  
Distribution Studies

Abstract The catabolism of human tissue plasminogen activator (t-PA) was studied in mice. The clearance of t-PA labeled with iodine 125 was rapid (t1/2). The clearance of phenylmethylsulfonyl-125I-t-PA, which is active site-inhibited, was identical to the active enzyme. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that the vast majority of 125I-t-PA injected into the circulation was present as free enzyme and not in a complex with inhibitors. The clearance of 125I-t-PA was unaltered by large molar excesses of several ligands of known clearance specificities, including macroalbumin, asialoorosomucoid, and diisopropylphosphorylthrombin and was also not altered in the presence of a 1,000-fold molar excess of unlabeled t-PA. Organ distribution studies demonstrated that the early rapid clearance of 125I-t-PA occurred in hepatocytes, followed by a later renal phase of clearance. The clearance of 125I-urokinase (UK) also was studied and was very similar in all aspects to the clearance of 125I-t-PA. These results suggest that both t-PA and UK are cleared from the circulation by unique nonsaturable processes localized in the liver that are independent of the proteinase active site.

scholarly journals The reactive serine residue of epidermolytic toxin A

1990 ◽  
Vol 269 (2) ◽  
pp. 535-537 ◽  
Author(s):  
C J Bailey ◽  
T P Smith
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Functional Relationship ◽  
Sequence Data ◽  
Serine Residue ◽  
Toxin A ◽  
Amino Acid Sequence Data

Comparison of amino acid sequence data suggested that there may be a functional relationship between the staphylococcal epidermolytic toxins and V8 proteinase. The hypothesis was tested by treating epidermolytic toxin with di-isopropyl phosphorofluoridate, which bound specifically at serine-195, the homologue of the active-site serine residue of V8 proteinase.

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