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. 1999 Mar 16;96(6):3160-4.
doi: 10.1073/pnas.96.6.3160.

A model of human phenylalanine metabolism in normal subjects and in phenylketonuric patients

S Kaufman  1
Affiliations

A model of human phenylalanine metabolism in normal subjects and in phenylketonuric patients

S Kaufman. Proc Natl Acad Sci U S A. .

Erratum in

  • Proc Natl Acad Sci U S A 1999 Sep 28;96(20):11687

Abstract

The derivation of a quantitative model of phenylalanine metabolism in humans is described. The model is based on the kinetic properties of pure recombinant human phenylalanine hydroxylase and on estimates of the in vivo rates of phenylalanine transamination and protein degradation. Calculated values for the steady-state concentration of blood phenylalanine, rate of clearance of phenylalanine from the blood after an oral load of the amino acid, and dietary tolerance of phenylalanine all agree well with data from normal as well as from phenylketonuric patients and obligate heterozygotes. These calculated values may help in the decision about the degree of restriction of phenylalanine intake that is necessary to achieve a satisfactory clinical outcome in classical patients and in those with milder forms of the disease.

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Figures

Figure 1
Figure 1
Phenylalanine metabolism. Reaction 1 is catalyzed by phenylalanine hydroxylase. Reaction 2 is catalyzed by phenylalanine transaminase.
Figure 2
Figure 2
Calculated rates of clearance of a load of phenylalanine for controls and for individuals with different genotypes. A, controls; B, subject with zero transaminase activity; C, subject with 40% of control PAH activity; D, subject with 0% of control PAH activity.
See this image and copyright information in PMC

References

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