Which step is catalyzed by the enzyme responsible for the Met 3 mutant?
A)homoserine → cysteine
B)cysteine → cystathionine
C)cystathionine → homocysteine
D)homocysteine → methionine
E)methionine → homoserine

Question

Which step is catalyzed by the enzyme responsible for the Met 3 mutant? 
A)homoserine → cysteine 
B)cysteine → cystathionine 
C)cystathionine → homocysteine 
D)homocysteine → methionine 
E)methionine → homoserine

Quizplus · Accepted Answer

The Met 3 mutation affects the enzyme responsible for converting cysteine to cystathionine, which is step 2 in the methionine biosynthesis pathway. Therefore, the correct answer is B.

Which Step Is Catalyzed by the Enzyme Responsible for the Met