[Use of a new amino acid mixture in the diet therapy of patients with classical phenylketonuria].

The treatment of classic PKU is based on the dietary restriction of phenylalanine. The present study was planned to evaluate the effectiveness of a new amino acid mixture (ASP-Nestlé) in the dietary treatment of ten PKU patients (age 2 to 9 years, mean 5 years). The children were given this product for a minimum of 3 and a maximum of 12 months (mean 8 months).

Renaturation and urea-induced denaturation of 20 beta-hydroxysteroid dehydrogenase studied in solution and in the immobilized state.

Tetrameric 20 beta-hydroxysteroid dehydrogenase (17,20 beta,21-trihydroxysteroid:NAD+ oxidoreductase, EC 1.1.1.

[Attempts to characterize dexamethasone receptors present in rat kidney cytosol].

Density gradient centrifugation analysis has been used to study rat kidney receptors for dexamethasone. Density gradients performed with cytosol incubated with 3H-dexamethasone in a Tris 10 mM, EDTA 1.5 mM, glycerol 5%, monothioglycerol 12 mM (pH 7.

Free amino acids in liver of patients with homocystinuria due to cystathionine synthase deficiency: effects of vitamin B6.

Patients with homocystinuria due to cystathionine synthase deficiency do not have free homocystine in the liver when it is present in high concentrations in the plasma and the urine. The liver of these patients is capable of maintaining normal concentrations of cystine at a time when the plasma cystine concentration is severely reduced. There is an increase in the methionine concentration of the liver which is reduced to normal concentrations during pyridoxine therapy.

Homocysteine and cysteine loads in patients with homocystinuria due to cystathionine synthase deficiency: effects of vitamin B-6.

The metabolic response of patients with homocystinuria due to cystabhionine synthase deficiency to oral loads of homocysteine indicates: that even severely affected patients with homocystinuria have pools of cystine in their tissues; that control of sulfur amino acid metabolism favors increased concentrations of methionine rather than homocystine in the plasma; and that even patients who apparently are not B-6-responsive respond differently to the loads of homocysteine when challenged during B-6-treatment compared with their response before B-6 treatment. Loading tests with homocysteine indicate that B-6 treatment be of some benefit even in individuals who do not have an obvious biochemical response to such therapy.

Cystathionine beta-synthase deficiency: a qualitative abnormality of the deficient enzyme modified by vitamin B6 therapy.

The thermostability of cystathionine synthase and the effect of pyridoxal phosphate (PLP) on this thermostability were investigated in extracts of normal human liver and in extracts of liver, both before and during pyridoxine (vitamin B6) therapy, from members of a family with three clinically and biochemically typical, B6-responsive, synthase-deficient sibs. Incubation of crude extracts of normal liver at 55 degrees (preincubation) for 3-4 min before assay consistently resulted in a more than 2-fold increase in specific activity (activation) of cystathionine synthase (Fig. 1).