Allosteric regulation of 6-phosphofructo-1-kinase activity of fat body and flight muscle from the bloodsucking bug Rhodnius prolixus.
6-Phosphofructo-1-kinase (phosphofructokinase; PFK) activity from Rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. The activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 +/- 1.4 U/mg) than in fat body extracts (3.6+/-0.4 U/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. Muscle extracts are more responsible than fat body to ATP and fructose 6-phosphate, both substrates of PFK. Allosteric regulation exerted by different effectors such as ADP, AMP and fructose 2,6-phosphate presented a singular pattern for each tissue. Optimal pH (8.0-8.5) and sensitivity to pH variation was very similar, and citrate was unable to inhibit PFK activity in both extracts. Our results suggest the existence of a particular PFK activity for each tissue, with regulatory patterns that are consistent with their physiological roles.
Alves
Gutemberg G
GG
Laboratório de Enzimologia e Controle do Metabolismo, Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brasil.
Marinho-Carvalho
Monica M
MM
Atella
Georgia C
GC
Silva-Neto
Mario A C
MA
Sola-Penna
Mauro
M
D000494:Allosteric Regulation / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D005216:Fat Body / Q000201:enzymology*; D007700:Kinetics; D018482:Muscle, Skeletal / Q000201:enzymology*; D010732:Phosphofructokinase-1 / Q000378:metabolism* / Q000502:physiology*; D012239:Rhodnius / Q000201:enzymology*
D010732:Phosphofructokinase-1