No, green drinks do not deactivate Miracle-Mineral-Supplement , any more than the other juices Humble mentions. (I am talking here about pure green drinks that basically have nothing in them other than grasses and veggies).
I have been using Alkaline on and off for Miracle-Mineral-Supplement also. Here is what I do: mix the Miracle-Mineral-Supplement and citric acid , cover and let sit for 3 mins. When I remove the cover, the MMS appears yellowish, and smells strongly. I then add about 4 ounces of distilled water, then about 1/5 teaspoon of Alkalive, stir, and drink.
This definitely does not deactivate the MMS - you can still taste it a little, depending upon how many drops you are using. If you want to run a test, try increasing the number of drops - if you are at 8, then go to 12 or higher - and be sure to cover the glass while the MMS "brews". (But be ready for some detox symptoms, possibly nausea and even vomitting).
Anyhow, if you are not getting any detox, it may be because you are a very healthy person. Do you have health conditions/issues that you are working on?