Abstract
The stability of AMP: pyrophosphate phosphoribosyltransferases (AMP pyrophosphorylase) from erythrocytes of normal subjects and patients with Lesch-Nyhan disease has been studied. Storage of intact cells, but not lysates, led to increased heat stability of the normal but not the Lesch-Nyhan enzyme. Passage of lysates of stored normal erythrocytes through Sephadex gave a further increase in the heat stability of AMP pyrophosphorylase. Boiled extracts of stored erythrocytes contained a potent destabilizer of the enzyme which was identified as hypoxanthine. A heat stable form of AMP pyrophosphorylase was generated by pre-incubation with 5-phosphoribosyl i-pyrophosphate, a substrate. These observations suggest that the level of AMP pyrophosphorylase in the erythrocyte may be controlled by the relative concentrations of stabilizer and destabilizer. A variety of purine derivatives were destabilizers of the enzyme. Compounds with 6-amino substituents were active with the normal and Lesch-Nyhan enzyme but 6-hydroxypurines affected only normal AMP pyrophosphorylase. AMP pyrophosphorylases were purified 200-fold from normal and Lesch-Nyhan erythrocytes. The purified enzymes retained some of the differences in stability seen with crude lysates, but the destabilizing effect of purines was lost.
Original language | English (US) |
---|---|
Pages (from-to) | 163-174 |
Number of pages | 12 |
Journal | BBA - General Subjects |
Volume | 279 |
Issue number | 1 |
DOIs | |
State | Published - Aug 18 1972 |
Externally published | Yes |
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology