epistasis and purple corn....?

Question

my notes say: need two different enzymes working together to produce purple corn. what does this mean?

huh??? lol thanks

Answer 1

It means that the metabolic pathway that produces the purple pigment has two steps, each one catalyzed by a different enzyme. There are lot of ways this could work.

A--> B --> C
A could be a colorless compound which is converted by the first enzyme into something else which is then converted into a purple compound (C) by the second enzyme.

Alternatively, you could have something like:

A-->B
C-->D
Where B is red and D is blue (both formed from colorless compounds) so that only if both enzymes are working do you see a purple color.

You can distinguish between these possibilities by looking at corn that has only one of the enzymes and not the other...