Isolation, characterization, and cDNA cloning of a vampire bat salivary plasminogen activator.
Vampire bat saliva contains a plasminogen activator that presumably assists these hematophagous animals during feeding. Here, we report that the vampire bat salivary plasminogen activator, Bat-PA, is homologous to tissue-type plasminogen activator (t-PA) but contains neither a kringle 2 domain nor a plasmin-sensitive processing site. Three Bat-PA species corresponding to full-length, finger-, and finger- epidermal growth factor homology domain- forms of t-PA have been isolated. Bat-PA(H), the full-length form, was purified and its activity has been characterized. Bat-PA(H) and t-PA are of similar efficacy when monitored for their abilities to catalyze plasminogen activation in the presence of a fibrin cofactor. Interestingly, Bat-PA activity toward plasminogen is stimulated 45,000-fold in the presence of fibrin I; the corresponding value for t-PA is only 205-fold. Bat-PA(H) is the only Bat-PA species which binds tightly to fibrin, although each of the three species exhibit remarkable stimulation by a fibrin cofactor.
Gardell
S J
SJ
Department of Biological Chemistry, Merck Sharp & Dohme Research Laboratories, West Point, Pennsylvania 19486.
Duong
L T
LT
Diehl
R E
RE
York
J D
JD
Hare
T R
TR
Register
R B
RB
Jacobs
J W
JW
Dixon
R A
RA
Friedman
P A
PA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002685:Chiroptera; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification*; D005796:Genes; D008969:Molecular Sequence Data; D010960:Plasminogen Activators / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D013363:Submandibular Gland / Q000201:enzymology*; D010959:Tissue Plasminogen Activator / Q000235:genetics
D004247:DNA; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator