A mutation of angiotensinogen in a patient with preeclampsia leads to altered kinetics of the renin-angiotensin system.
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Inoue I, Rohrwasser A, Helin C, Jeunemaitre X, Crain P, Bohlender J, Lifton RP, Corvol P, Ward K, Lalouel JM
A mutation of angiotensinogen in a patient with preeclampsia leads to altered kinetics of the renin-angiotensin system.
J Biol Chem. 1995 May 12;270(19):11430-6.
- PubMed ID
- 7744780 [ View in PubMed]
- Abstract
Angiotensinogen exhibits genetic linkage to and association with essential hypertension and preeclampsia, a common hypertensive disorder of pregnancy; however, the polymorphisms detected thus far provide no functional clues. In a preeclamptic patient, we have identified a mutation leading to the replacement of leucine by phenylalanine at position 10 of mature angiotensinogen (L10F), the site of renin cleavage. Kinetic analyses of the enzymes of the renin-angiotensin system, using either model peptides or full-length substrates, show that this mutation significantly alters the reactions with both renin and angiotensin-converting enzyme. For the renin reaction on a full-length substrate, this substitution leads to a 10-fold decrease in Km (from 1.1 to 0.09 microM) and a 5-fold decrease in kcat (from 1.0 to 0.22 s-1); as a result, catalytic efficiency (kcat/Km) is increased by a factor of 2 (1.1 versus 2.4 microM-1 s-1). In the reaction of angiotensin-converting enzyme on angiotensin decapeptides, the substitution has no effect on Km (38.0 versus 30.0 microM), but increases kcat and catalytic efficiency > 2-fold (kcat = 15.0 versus 37.0 s-1; kcat/Km = 0.41 versus 1.23). The renin-angiotensin system, challenged by the profound physiological adaptations of pregnancy, is perturbed in preeclampsia; consequently, the L10F mutation may promote this condition in carrier subjects.