Maximal activities of glutaminase, citrate synthase, hexokinase, phosphofructokinase and lactate dehydrogenase in skin of rats and mice at different ages.

The activities of key glycolytic enzymes are, in general, similar at the three different ages of the animals used in this work (very young, adult and old). Glutaminase is present in skin of both mice and rats, but the activity was much lower in adult animals compared to the very young or the old. It is suggested that this activity is important for the provision of nitrogen for the de novo synthesis of purine and pyrimidine nucleotides during the growth of skin in the young animal and for DNA repair in the old animals; it might be important in the adult skin in response to wound healing.