Rma. Streatfeildjames et al., ANGIOTENSINOGEN CLEAVAGE BY RENIN - IMPORTANCE OF A STRUCTURALLY CONSTRAINED N-TERMINUS, FEBS letters, 436(2), 1998, pp. 267-270
Angiotensinogen, a plasma serpin, functions as a donor of the decapept
ide angiotensin I, which is cleaved from the N-terminus by renin, To a
ssess the contribution of the serpin framework to peptide cleavage we
produced a chimaeric molecule of alpha(1)-antitrypsin carrying the ang
iotensinogen N-terminus and determined the kinetic parameters for angi
otensin I release, The K-m for plasma angiotensinogen was 18-fold lowe
r than for the chiroaeric protein while the catalytic efficiency was f
our-fold higher. We also show that Cys-18 participates in a disulphide
bond and propose that constraints on the N-terminus profoundly affect
the interaction with renin. (C) 1998 Federation of European Biochemic
al Societies.