Related Experiment Video
Updated: Aug 16, 2026
Extraction of Venom and Venom Gland Microdissections from Spiders for Proteomic and Transcriptomic Analyses
Published on: November 3, 2014
Isolation of a proteinase with plasminogen-activating activity from Lachesis muta muta (bushmaster) snake venom
E F Sanchez1, C I Santos, A Magalhaes
1Centro de Pesquisa e Desenvolvimento, Fundacão Ezequiel Dias, Belo Horizonte, MG, Brazil. eladio@funed.mg.gov.br
Abstract:
A plasminogen activator enzyme (LV-PA) from Lachesis muta muta venom was purified to homogeneity using gel filtration and anion exchange chromatography. SDS-PAGE under reducing conditions showed a single protein band with an Mr of 33,000 Da. It is an acidic glycoprotein which activates plasminogen to plasmin indirectly, functioning via prior formation of a molecular complex, known as plasminogen activator. The purified preparation catalyzes the hydrolysis of several p-nitroanilide peptide substrates containing Lys at the scissile bond. In contrast, no hydrolysis was detected on the synthetic substrates TAME and BAPNA, which contain arginine. By the use of the plasmin-specific chromogenic substrate Tos-Gly-Pro-Lys-pNA, the preparation had a plasmin-like activity of 0.68 U/mg, which was 35.8-fold higher than that of the crude venom from which it was prepared. In vitro, fibrin hydrolysis using LV-PA as plasminogen activator displayed more similarity with the effect produced by streptokinase (SK). SDS-PAGE (10%) analysis showed a 115-kDa complex formation after incubation of plasminogen with either LV-PA or SK. At a molar ratio of 50:1 (fibrinogen:enzyme), the preparation exhibited weakly fibrinogenolytic activity. However, LV-PA is distinguished from thrombin in that it does not clot fibrinogen. After incubation of LV-PA with platelet-rich plasma, the enzyme (2 microM) showed no effect on platelet aggregation induced by ADP, epinephrine, or collagen. Comparison of the N-terminal sequence of LV-PA with other snake venom plasminogen activators revealed that LV-PA exhibits a high degree of sequence identity with the TsVPA from Trimeresurus stejnegeri (90%) and with the Haly-PA from Agkistrodon halys (85%). LV-PA also has homology with other snake venom serine proteinases such as the thrombin-like/gyroxin analogue (38%) from bushmaster venom and with other coagulation serine proteases. The proteinase was readily inhibited by treatment with p-nitrophenyl p-guanidinebenzoate, p-aminobenzamidine, and phenylmethanesulfonyl fluoride but was not affected by metal chelators.
Insights
A novel plasminogen activator enzyme (LV-PA) from Lachesis muta muta venom was purified and characterized. This enzyme exhibits potent plasmin-like activity and shows sequence homology with other snake venom serine proteinases.
Area of Science:
- Biochemistry
- Enzymology
- Snake Venom Research
Background:
- Snake venom contains diverse enzymes with various biological activities.
- Plasminogen activators are crucial in fibrinolysis, the breakdown of blood clots.
- Understanding novel activators can offer insights into hemostasis and potential therapeutic applications.
Purpose of the Study:
- To purify and characterize a novel plasminogen activator enzyme from Lachesis muta muta venom.
- To investigate its enzymatic properties, substrate specificity, and mechanism of action.
- To compare its sequence and activity with known plasminogen activators and other snake venom enzymes.
Main Methods:
- Purification of LV-PA using gel filtration and anion exchange chromatography.
- SDS-PAGE for molecular weight determination.
- Assays for enzymatic activity on synthetic substrates and plasminogen activation.
- Analysis of fibrinogenolytic and platelet aggregation effects.
- N-terminal amino acid sequencing and homology comparison.
Main Results:
- LV-PA was purified to homogeneity with a molecular weight of 33,000 Da.
- The enzyme indirectly activates plasminogen to plasmin with significant plasmin-like activity (35.8-fold higher than crude venom).
- LV-PA shows specificity for Lys-containing substrates and forms a complex with plasminogen, similar to streptokinase.
- It exhibits weak fibrinogenolytic activity but does not clot fibrinogen and does not affect platelet aggregation.
- N-terminal sequencing reveals high homology (90%) with TsVPA and 85% with Haly-PA, indicating it's a snake venom serine proteinase.
Conclusions:
- LV-PA is a potent, acidic glycoprotein plasminogen activator from Lachesis muta muta venom.
- Its mechanism of action and substrate specificity distinguish it from thrombin and other venom enzymes.
- The high sequence identity suggests a conserved evolutionary origin for these snake venom activators.
