[Study of hereditary fructose intolerance by methods of molecular biology].

Fructose intolerance is caused by a deficit of the liver aldolase B enzyme. Its molecular mechanisms were studied at different sites: The protein was studied by a method combining electrophoresis, transfer and immunology. It was present in the 15 cases examined.

Molecular studies on galactose 1 phosphate uridylyl transferase from normal and mutant subjects. An immunological approach.

The mutant forms of uridylyl transferase of eight galactosemic patients and two 'Rennes' variants were characterized with regard to the presence and level of immunoreactive protein, the apparent subunit molecular weight and the isoelectric point. Semi-purified haemolysates were studied by various electrophoretic techniques, then proteins were electrophoretically transferred on to nitrocellulose filters. They were treated with specific anti-transferase antibodies, and then with radioiodinated protein A, followed by autoradiography.

Pyridoxal 5' phosphate involvement in age-related modifications of tyrosine aminotransferase: multiple form patterns.

Multiple form patterns of tyrosine aminotransferase were studied in senescent and adult rat liver. Two main modifications were described for "old" rat enzyme: (i) appearance of a new molecular form, specific for old rats, eluted after adult form III and having other properties identical to this form; (ii) disappearance of intermediate forms II and III after enzyme induction; this result seems to be due to acceleration of the conversion process. Vitamin B6 deficiency of old rats explain this and other (previously described) post-translational modifications of "old" tyrosine aminotransferase.

DNA methylation and gene expression.

In the field of studies of the mechanisms of gene expression, much recent work using the methods of genetic engineering, have suggested the hypothesis of a role of DNA methylation (on some cytosines) in the control of gene activity. Undermethylation is generally accompanied by gene expression. A review of studies on DNA methylation in some physiopathologic conditions (such as development and cancer) and of recent therapeutic trials in beta thalassemia, allows to conclude that there is a correlation between DNA methylation pattern and gene expression, rather than a direct causal effect.

Properties of purified tyrosine aminotransferase from adult and senescent rat liver.

Induced tyrosine aminotransferase from adult and old rat liver was purified and its properties were studied. No differences could be detected for any physicochemical properties studied, i.e.