<prompt> Abnormal base in tRNA isDihydrouracilOrotic acidMethyl XanthineCystine  <response>: The D Arm or DHU region is so named due to the presence of a dihydrouridine in that areaThe DHU arm serves as the recognition site for the enzyme which adds the amino acidRef: DM Vasudevan, 7th edition, page no: 597 