Abstract
The salivary complex of the leech Haementeria depressa produces potent anticoagulant components. Among them, a protein named lefaxin inhibits factor Xa (FXa). Lefaxin was purified to homogeneity from dissected salivary complexes by gel filtration in Sephadex G-150 followed by two ion exchange chromatography steps in Mono-Q. Inhibition of FXa by lefaxin was demonstrated by the inhibition of its amidolytic activity, measured with chromogenic substrate S-2765 (apparent K(I) of 4 nM), and of its ability to inhibit thrombin generation in the prothrombinase complex (EC50 of 40 nM). Lefaxin has a molecular weight of 30 kDa and an isoelectric point of 5.7. It is made of a polypeptide chain whose N-terminal sequence shows no similarity with that of other FXa inhibitors (antistasin and ghilianten) isolated from leech saliva. On the other hand, the N-terminal sequence of lefaxin presents significant sequence similarity with nitric oxide carrier proteins myohemerythrin from the annelid Nereis diversicolor and prolixin S from the triatoma Rhodnius prolixus. Interestingly, prolixin S also proved to be an anticoagulant protein acting on FXa.
Publication types
-
Comparative Study
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Sequence
-
Animals
-
Anticoagulants / pharmacology*
-
Blood Coagulation / drug effects*
-
Chromatography, Gel
-
Chromatography, Ion Exchange
-
Chromogenic Compounds / metabolism
-
Factor Xa Inhibitors*
-
Helminth Proteins / isolation & purification*
-
Helminth Proteins / pharmacology
-
Hemeproteins / chemistry
-
Hemeproteins / pharmacology
-
Hemerythrin / analogs & derivatives
-
Hemerythrin / chemistry
-
Humans
-
Leeches / chemistry*
-
Molecular Sequence Data
-
Oligopeptides / metabolism
-
Saliva / chemistry*
-
Salivary Proteins and Peptides / chemistry
-
Salivary Proteins and Peptides / isolation & purification*
-
Salivary Proteins and Peptides / pharmacology
-
Sequence Alignment
-
Sequence Homology, Amino Acid
-
Serine Proteinase Inhibitors / isolation & purification*
-
Serine Proteinase Inhibitors / pharmacology
-
Species Specificity
-
Substrate Specificity
-
Thromboplastin / antagonists & inhibitors
Substances
-
Anticoagulants
-
Chromogenic Compounds
-
Factor Xa Inhibitors
-
Helminth Proteins
-
Hemeproteins
-
Hemerythrin
-
Oligopeptides
-
Salivary Proteins and Peptides
-
Serine Proteinase Inhibitors
-
lefaxin
-
myohemerythrin
-
nitrophorin
-
benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide
-
Thromboplastin