Inhibition of DNA synthesis by aspirin in Swiss 3T3 fibroblasts.

In Swiss 3T3 fibroblasts, aspirin inhibited proliferation induced by the complete mitogenic factors platelet-derived growth factor (PDGF) and bombesin. Aspirin decreased the maximum mitogenic effect of bombesin without modifying the concentration necessary to obtain half maximal DNA synthesis stimulation. In contrast, aspirin only decreased mitogenesis at subsaturating PDGF concentrations.

Metabolism of glycerate 2,3-P2--XI. Essential amino acids of pig phosphoglycerate mutase isozymes.

Phosphoglycerate mutase isozymes (types M, B and MB) from pig tissues are inactivated upon treatment with reagents specific for histidyl, arginyl and lysyl residues. Their mutase, 2,3-bisphosphoglycerate synthase and 2,3-bisphosphoglycerate phosphatase activities are concurrently lost, although some differences exist in the rate of inactivation. No significant differences are observed between the isozymes.

Metabolism of glycerate-2,3-P2--VII. Enzymes involved in the metabolism of glycerate-2,3-P2 in cat tissues.

The levels of the enzymes involved in the metabolism of glycerate-2,3-P2 (phosphoglycerate mutase, bisphosphoglycerate synthase-phosphatase and bisphosphoglycerate phosphatase) in cat and in pig tissues are different. The main difference is the low level of bisphosphoglycerate synthase-phosphatase in cat tissues. As a consequence, in contrast with pig erythrocytes, in cat erythrocytes, both the synthesis and the breakdown of glycerate-2,3-P2 are mainly controlled by phosphoglycerate mutase.

Metabolism of glycerate-2,3-P2--VI. Lysyl-specific reagents inactivate the phosphoglycerate mutase, glycerate-2,3-P2 synthase and glycerate-2,3-P2 phosphatase activities of rabbit muscle phosphoglycerate mutase.

Treatment of rabbit muscle phosphoglycerate mutase with trinitrobenzenesulfonate and with pyridoxal-5'-phosphate produces the concurrent loss of the three activities of the enzyme: phosphoglycerate mutase, glycerate-2,3-P2 synthase and glycerate-2,3-P2 phosphatase. With both reagents complete inactivation occurs with modification of about 3 moles of lysine per mole of enzyme. Inactivated phosphoglycerate mutase is unable to form the functionally active phosphoenzyme when mixed with glycerate-2,3-P2.