Ancylostoma caninum anticoagulant peptide: a hookworm-derived inhibitor of human coagulation factor Xa.
Human hookworm infection is a major cause of gastrointestinal blood loss and iron deficiency anemia, affecting up to one billion people in the developing world. These soil-transmitted helminths cause blood loss during attachment to the intestinal mucosa by lacerating capillaries and ingesting extravasated blood. We have isolated the major anticoagulant used by adult worms to facilitate feeding and exacerbate intestinal blood loss. This 8.7-kDa peptide, named the Ancylostoma caninum anticoagulant peptide (AcAP), was purified by using a combination of ion-exchange chromatography, gel-filtration chromatography, and reverse-phase HPLC. N-terminal sequencing of AcAP reveals no homology to any previously identified anticoagulant or protease inhibitor. Single-stage chromogenic assays reveal that AcAP is a highly potent and specific inhibitor of human coagulation, with an intrinsic K*i for the inhibition of free factor Xa of 323.5 pM. In plasma-based clotting time assays, AcAP was more effective at prolonging the prothrombin time than both recombinant hirudin and tick anticoagulant peptide. These data suggest that AcAP, a specific inhibitor of factor Xa, is one of the most potent naturally occurring anticoagulants described to date.
Cappello
M
M
Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA.
Vlasuk
G P
GP
Bergum
P W
PW
Huang
S
S
Hotez
P J
PJ
D000595:Amino Acid Sequence; D000722:Ancylostoma / Q000502:physiology*; D000818:Animals; D060829:Arthropod Proteins; D001777:Blood Coagulation / Q000187:drug effects; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D065427:Factor Xa Inhibitors; D015801:Helminth Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010455:Peptides / Q000494:pharmacology; D011517:Prothrombin Time; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D013987:Ticks
D060829:Arthropod Proteins; D065427:Factor Xa Inhibitors; D015801:Helminth Proteins; D006629:Hirudins; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D010455:Peptides; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; C094339:anticoagulant protein, Ancylostoma caninum; C063967:tick anticoagulant peptide