Tritium labelling and degradation studies of Dmt1‐endomorphin 2

Abstract

AbstractTwo tritiated derivatives of Dmt1‐endomorphin 2 (Dmt1‐EM2) were prepared by the catalytic tritiodehalogenation of 3′,5′‐diiodo‐Dmt1‐EM2 and the saturation of 3,4ΔPro2‐Dmt1‐EM2, resulting in [3′,5′‐3H2]Dmt1‐EM2 and [3H2]Pro2‐Dmt1‐EM2 with specific activities of 2.88 TBq/mmol (77.8 Ci/mmol) and 1.95 TBq/mmol (52.8 Ci/mmol), respectively. 3′,5′‐Diiodo‐Dmt1‐EM2 was synthesized by the chloramine T method from Dmt1‐EM2. 3,4ΔPro2‐Dmt1‐EM2 was synthesized by using the Merrifield solid‐phase method. The distributions of the tritium in the labelled peptides were investigated by reversed‐phase high‐performance liquid chromatography after acidic hydrolysis. The stability of Dmt1‐EM2 in a rat brain membrane homogenate was also determined. Copyright © 2007 John Wiley & Sons, Ltd.