Final answer:
Non-LTR and LTR retrotransposons both encode for the enzyme reverse transcriptase.
Step-by-step explanation:
A common enzyme that non-LTR and LTR retrotransposons encode for is reverse transcriptase. This enzyme is responsible for generating a complementary DNA (cDNA) copy from the retrotransposon's RNA intermediate. Reverse transcriptase is essential for the retrotransposition process, which involves the insertion of the transposable element into new DNA locations.