M. Yadollahi-farsani et al., Polymorphic forms of human ADP-ribosyltransferase-1 - Differences in theircatalytic activities revealed by labeling of membrane-associated substrates, EUR J BIOCH, 262(2), 1999, pp. 342-348
Full length cDNA encoding ADP-ribosyltransferase-1 (ART1) was generated fro
m human skeletal muscle. A single base variation from the published sequenc
e was observed (C770-->T), and was established as a polymorphism by the scr
eening of a population of 50 Caucasians. The base variation predicted a non
conservative substitution of Leu for Pro at codon 257. Cell lines with stab
le and doxycycline-inducible expression of the two polymorphic forms of ART
1 were generated from Chinese hamster V79 cells, and exploited in studies t
o compare the activities of ART1-Pro257 and ART1-Leu257. The results reveal
ed no differences in the capacity of phosphoinositide-specific phospholipas
e C to cleave the two ART1 isoforms from the plasma membrane. Furthermore,
the capacities of ART1-Pro257 and ART1-Leu257 to ADP-ribosylate agmatine or
fibroblast growth factor-2 were similar. Differences in the catalytic acti
vities of ART1-Pro257 and ART1-Leu257 were however, identified when measure
ments were made of their capacities to ADP-ribosylate membrane-associated p
roteins on the surface of V79 cells. Protein(s) of molecular mass 80-110 kD
a were more extensively ADP-ribosylated by ART1-Pro257 than ART1-Leu257, in
accordance with the V-max (59.5 +/- 5.5 and 37.0 +/- 3.0) and K-m values (
12.5 +/- 4.5 and 5.0 +/- 1.9) for ART1-Pro257 and ART1-Leu257, respectively
.