Formation and ultrastructure of enzymically active polymers of pig renal glutaminase

Highly purified pig renal glutaminase has been subjected to electron microscopy. It is shown that the polymers formed after addition of phosphate-borate to enzyme dissolved in Tris-HCl buffer consist of long, double-stranded helices. Addition of phosphate to the Tris-HCl form of the enzyme probably induces the formation of dimers of the Tris-HCl units. It is further demonstrated that the rate of formation of the phosphate form and phosphate-borate form from Tris-HCl units, closely follows the increase in the catalytic activity of the enzyme.