- 1We assayed active and total (i.e. active plus succinylated) 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase in mitochondria isolated from foetal, neonatal, suckling or weaned rats.
- 2HMG-CoA synthase was substantially succinylated and inactivated in mitochondria isolated from termfoetal, (1-h-old, 6-h-old, 1-day-old) neonatal, suckling and high carbohydrate/low-fat (hc)-weaned rats. Succinylation of HMG-CoA synthase was very low in mitochondria isolated from the livers of foetal, 30-min-old neonatal and high-fat/carbohydrate-free (hf)-weaned rats.
- 3There was a negative correlation between active HMG-CoA synthase and succinyl-CoA content in mitochondria isolated from term-foetal, suckling and hc-weaned rats.
- 4Differences in active enzyme could not be entirely accounted for by differences in succinylation and inactivation of the synthase. Immunoassay confirmed that the absolute amounts of mitochondrial HMG-CoA synthase increased during the foetal/neonatal transition and decreased with hc weaning. The levels remained elevated with hf weaning.
- 5From these data we propose that mitochondrial HMG-CoA synthase is controlled by two different mechanisms in young rats. Regulation by succinylation provides a mechanism for rapid modification of existing enzyme in response to changing metabolic states. Changes in the absolute amounts of HMG-CoA synthase provide a more long-term control in response to nutritional changes.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.
high carbohydrate/low fat
high fat/carbohydrate free
respiratory control ratio
3-Hydroxy-3-methylglutaryl-CoA synthase (EC 184.108.40.206)
phosphotransacetylase (EC 220.127.116.11)
carnitine palmitoyl-transferase I (EC 18.104.22.168)