Prostatic kallikrein hK2, but not prostate-specific antigen (hK3), activates single-chain urokinase-type plasminogen activator.
Our work was undertaken to compare the relative efficiency of 2 purified prostatic kallikreins, namely, hK2 and prostate-specific antigen (PSA or hK3), in the activation of single-chain urokinase (scuPA). We found that hK2 converts scuPA into an active enzyme with an efficiency equal to approximately 1/50 that of plasmin. During the activation of scuPA by hK2, two fragments of 33 and 22 kDa were generated. The NH2-terminal amino acid sequence of the 33 kDa fragment showed that hK2 cleaved scuPA between Lys158 and Ile159. In contrast to a previous report by another group, our purified hK3 preparation containing no trypsin-like contaminants was totally unable to activate scuPA. Our results show that kallikrein hK2 has plasmin-like activity and suggest that it could be the initiator of a proteolytic cascade leading to prostatic cancer invasion.
Frenette
G
G
Hormonal Bioregulation Laboratory, CHUL Research Center and Laval University, Sainte-Foy, Quebec, Canada.
Tremblay
R R
RR
Lazure
C
C
Dube
J Y
JY
D000595:Amino Acid Sequence; D004789:Enzyme Activation / Q000187:drug effects; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007610:Kallikreins / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism; D011467:Prostate / Q000201:enzymology*; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry / Q000378:metabolism*
D010446:Peptide Fragments; D010958:Plasminogen; D007610:Kallikreins; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator