Stimulation of the sodium-potassium pump by trypsin in low potassium type erythrocytes of goats.
1. Treatment of low K goat red cells with trypsin stimulated the Na-K pump more than twofold. Dose dependence and time course experiments indicated a half-maximal stimulation at 1.6 mg trypsin/ml. (37 degrees C, 3 hr), and a maximum effect after 5 hr (10 mg/ml). 2. Trypsin had only a small and variable effect on the ouabain-insensitive component of K influx. 3. The Na-K pump activity of high K goat red cells was not affected by trypsinization. 4. When intracellular K was varied by the PCMBS technique, it was found that the trypsin stimulation was greatest (2-5-fold) in cells with the highest K (40 m-mole/1. cells) and lowest (1.1-fold) in cells with low K (<1 m-mole/1. cells). 5. The trypsin effect was reversed by nystatin treatment or hypotonic lysis. 6. Trypsin did not increase the number of ouabain-binding sites. 7. It is concluded that trypsinization modifies the L antigen in low K goat red cells to decrease the apparent internal affinity for K of the Na-K pump in these cells.
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001693:Biological Transport, Active / Q000187:drug effects; D004912:Erythrocytes / Q000378:metabolism*; D006041:Goats / Q000378:metabolism*; D007700:Kinetics; D009761:Nystatin / Q000494:pharmacology; D010042:Ouabain / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013268:Stimulation, Chemical; D014357:Trypsin / Q000494:pharmacology*
D009761:Nystatin; D010042:Ouabain; D012964:Sodium; D014357:Trypsin; D011188:Potassium