Comparisons of Phosphofructokinases-1 from Rabbit, Chicken, and Fish

Background: Previous studies suggested that glycogen storage was facilitated by ascorbate inhibition of phosphofructokinase-1 (PFK-1) in resting mammalian muscle; these studies showed that purified PFK-1 from fish or chicken muscle has properties similar to PFK-1 from mammalian muscles. Materials and Methods: The enzymes utilized in the assay systems came from Sigma-Aldrich Co. Rabbit (Oryctolagus cuniculus) muscle G-actin (A 2522) was free of aldolase, LDH (EC 1.1.1.28) or AK (EC 2.7.4.3) activity and rabbit muscle aldolase (EC 4.1.2.13) was free of AK (EC 2.7.4.3) and LDH activity. Rabbit muscle PFK-1 (RPFK-1), chicken (Gallus gallus) muscle PFK- 1 (CPFK-1) and Pacific red snapper (Lutjanus peru) muscle PFK-1 (FPFK-1) used in these tests were prepared from frozen tissues with modifications of a method. AK, LDH, and aldolase activity were absent in purified FPFK- 1 and CPFK-1 preparations. Results: It can be shown that the following enzymes associated with glycolysis are not inhibited by 0.1 M ascorbate under our conditions: rabbit muscle aldolase (EC 4.1.2.13); rabbit muscle glyceraldehyde 3-phosphate dehydrogenase (EC 1.2.1.12); rabbit muscle phosphoglucose isomerase (EC 5.3.1.9); rabbit muscle pyruvate kinase (EC 2.7.1.40); yeast hexokinase (EC 2,7.1.1); and yeast 3-phosphoglyceric phosphokinase (EC 2.7.2.3). Rabbit muscle enolase (EC4.2.1.11) is inhibited under our conditions. Conclusion: In summary, FPFK-1 and CPFK-1, possess characteristics and behaviors similar to RPFK-1, e.g., losses of activities due to dilutions and protections of some of these activity losses by rabbit muscle aldolase. These interactions of a mammalian aldolase with fish and a bird PFK-1’s suggests a conservative evolutionary relationship among aldolases and PFK-1’s.