Pulldown for zener voltage shifter
The first circuit is probably better, since the second creates a voltage divider. Warning: low voltage zeners have very soft "knees", i.e. they start conducting significantly well before the rated voltage. We will need to know the characteristics of the inputs and enable signal to know if this will work. 

If the enable is a standard CMOS input, it will probably have a worst case threshold of 70% of Vcc, or, 2.3V.

The zener V-I curve that I quickly found shows the voltage drop to be 20% less at 1 mA. R17 may limit the current to a lot less than 1 mA, unless your circuit input has a high voltage. We need to know the characteristics of the input. At what input threshold do you expect the enable to be logic 1? 

Edit: OK, if your input is 3.3 - 5V, then R17 is way too high. If you lower R17 it to 1k it may work. I can't find any zener I-V curves that show currents less than 1 mA, so knowing what happens when your input is near 3.3V is difficult to determine.

And I agree with sunnyskyguy, R24 isn't necessary.