The coexistence of Ser84 in renin and His13 in angiotensinogen brings a pH profile of two separate peaks to the reaction of human renin and sheep angiotensinogen.
The pH dependence and kinetics parameters of renin-angiotensinogen reactions were determined using wild-type and S84G mutant human renins and wild-type and H13Y mutant sheep angiotensinogens. It is explained in this report that (i) renin catalyzes acidic and basic reactions of which the optimum pHs are 5.5 and 7.5-8.2 respectively, both of which produce angiotensin I; (ii) Ser84 specific to human renin accelerates the acidic reaction by 75-110% through elevation of V(max), and shifts the optimum pH of the basic reaction from 7.5 to 8.0-8.2; and (iii) His13 specific to sheep angiotensinogen accelerates the acidic and basic reactions by 25-42% through reduction of K(m). It is concluded from these results that the coexistence of Ser84 in renin and His13 in angiotensinogen brings a pH profile of two separate peaks at pHs 5.5 and 8.2 to the reaction of human renin and sheep angiotensinogen.
Iwata
Hideyuki
H
United Graduate School of Agricultural Science, Gifu University, Yanagido, Gifu, Japan.
Nakagawa
Tsutomu
T
Yoshioka
Yuichiro
Y
Kagei
Kazufumi
K
Imada
Kenta
K
Nakane
Chiaki
C
Fujita
Hiromi
H
Suzuki
Fumiaki
F
Nakamura
Yukio
Y
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000808:Angiotensinogen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D003001:Cloning, Molecular; D017931:DNA Primers; D006639:Histidine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012083:Renin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012694:Serine; D012756:Sheep
D017931:DNA Primers; D000808:Angiotensinogen; D012694:Serine; D006639:Histidine; D012083:Renin