Amino-terminal fragment ( ATF, amino acid 1-135 ) was produced from pro-urokinase employing controlled Kellikrein
cleavage, followed by autolysis. The structure of ATF consists of two
individual modules: a growth factor domain (GFD) and a kringle
domain. The N-terminal GFD is responsible for localizing urokinase
and pro-urokinase on the cell surface by binding to
the u-PA receptor (u-PAR), which promotes monocyte
adhesion. Unlike homologous kringles of plasminogen and tissue plasmingen
activator, the ATF kringle dose
not bind to fibrin. Instead, the ATF kringle
has been shown to bind heparin. ATF has no effect on plasminogen
activation by urokinase, however, it is a
competitive inhibitor for the binding of urokinase
and pro-urokinase to u-PAR. N-terminal sequence
analysis on ATF was performed with a PE/BD Procise
494 HT Protein Sequencing System. The molecular weight of ATF is about 15,000 dalton.
Greater than 95% by SDS-PAGE.
The adhesion of U937 monocyte to plastic surface
was promoted by ATF. ATF binds unoccupied human u-PAR in a competitive
manner, against pro-urokinase and urokinase.
White lyophilized powder or solution.
The lyophilized powder is best stored desiccated below 0 °C. After it is
reconstituted with sterile water or other buffered solutions, it should be
stored at -20 °C.