Occurrence of the Crabtree effect in HeLa cells.
The occurrence of a Crabtree effect in HeLa cells was detected. Some properties of pyruvate kinase (PK) were also evaluated. Hexose phosphate, triose-phosphate and phosphoenolpyruvate (PEP) significantly decreased the oxygen consumption of digitonin-permeabilized HeLa cells, which were oxidizing succinate. The Crabtree effect promoted by PEP was concentration-dependent and was lowered by an increase of ADP concentration, suggesting a participation of PK. The dependence of fructose-1,6-bisphosphate (FDP) by HeLa cell PK was observed. The PK of HeLa cells was inhibited by L-alanine only in the absence of FDP, while in the presence of the metabolite, an increase in the activity was observed. PK was also inhibited in the presence of L-histidine and L-leucine, while L-serine promoted activation. L-Cysteine and L-phenylalanine also inhibited the PK of HeLa cells. This, together with the sigmoidal character in relation to substrate concentration, suggests the presence of the K-type of PK in HeLa cells.
Melo
R F
RF
Departamento do Bioquímica da Universidade Federal do Paraná Curitiba, Brasil.
Stevan
F R
FR
Campello
A P
AP
Carnieri
E G
EG
de Oliveira
M B
MB
D002455:Cell Division / Q000502:physiology; D019069:Cell Respiration / Q000502:physiology; D002474:Cell-Free System; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D011770:Pyruvate Kinase / Q000378:metabolism
D011770:Pyruvate Kinase; D005947:Glucose