Abstract: In this paper, the cooperative effects of effectors and pH on the activity of PEPCase and the differences in sensitivities of PEPCase to effectors in green and etiolated maize leaves were studied.It was discovered that the PEPCase in green leaves was more sensitive to G6P and Gly, but less sensitive to Mal than that in etiolated leaves (Fig 1,2,3,4).When etiolated leaves was exposed to light(3000 lx)for 3 hours, the sensitivity of PEPCase to G6P tended to be similar to that in green leaves(Fig 1)The PEPCase in green or etiolated leaves also showed different sensitivities to G6P,Gly and Mal when assayed at different PH, being more sensitive to G6P,Gly and Mal at lower pH (7.4) than at higher pH(9.2)(Fig,2,3,4).The sensitivity of PEPCase to G6P in green leaves at pH9.2 was similar to that in etiolated leaves at pH7.4(Fig.2).This suggested the involvement of cooperative effects of effector and pHon the activity of PEPCase.The reguiatory properties of PEPCase in etiolated leaves by effectors showed that the major function of PEPCase in etiolated leaves might be not to fix CO2 for photosynthesis.

Key words: Maize, PEPCase, Effector, pH, Green seedlings, Etiolated seedlings

CLC Number: 

• S562.01