Meeting Abstract
59.6 Tuesday, Jan. 6 Catechol-O-methyl transferase may play an important role in allowing Neotoma stephensi to specialize on juniper SKOPEC, MM*; NEBEKER, C; DEARING, MD; Weber State University; Weber State University; University of Utah micheleskopec@weber.edu
Dietary specialization is thought to be rare in mammalian herbivores because of limitations of their detoxification system in processing large doses of a single type of plant secondary compound. One species of woodrats, Neotoma stephensi, specializes on juniper (Juniperus monosperma) and therefore, must efficiently biotransform the terpenes present in juniper. Based on a previous study, we hypothesized that catechol-O-methyl transferase (COMT) is a candidate enzyme critical for biotransformation of terpenes found in juniper. COMT is a conjugation enzyme that conjugates a methyl group to its substrate; the loss of a methyl group as a conjugate may be less energetically costly than glucose or amino acid conjugates used by other conjugation enzymes. We measured the protein expression of COMT using western blots in N. stephensi fed either a 70% juniper diet or a terpene-free diet. We found that N. stephensi fed the 70% juniper diet had 2.5x the amount of COMT as the N. stephensi fed the terpene free diet (F1,6=17.928 p=0.005). Increased levels of COMT may be an adaptation that allows N. stephensi to use conjugation over functionalization. Conjugation enzymes have broader substrate acceptability and produce less reactive metabolites. COMT in particular does not result in the loss of a high energy conjugate like glucose or an amino acid.
