title: On the mechanism of formation of arterenone in insect cuticular hydrolyzates.
abstract: Arterenone (2-amino-3',4'-dihydroxy acetophenone) is an important hydrolytic product generated from lightly colored sclerotized cuticle that use N-acyldopamine derivatives for crosslinking reactions. It seems to arise from 1,2-dehydro-N-acetyldopamine (dehydro NADA) that has been crosslinked to the cuticular components. However, the mechanism of generation of arterenone, which has two protons on the α-carbon and no proton on the β-carbon atom from dehydro NADA crosslinks that have one proton each on these two side chain carbons, remained elusive and undetermined. To investigate the mechanism of this transformation, we synthesized specifically labeled β-deuterated dehydro NADA and incubated with Sarcophaga bullata cuticle undergoing larval puparial transformation. We also isolated the dimeric products formed during the tyrosinase-mediated oxidation of dehydro NADA. Hydrolysis of both β-deuterated dehydro NADA treated cuticle and β-deuterated dehydro NADA dimer generated arterenone as the major hydrolytic product. Liquid chromatography-mass spectrometric analysis of this arterenone revealed the retention of deuterium from the β-position of dehydro NADA at the α-carbon atom of arterenone. Hydrolysis of β-deuterated dehydro NADA also generated the labeled arterenone under oxidative conditions, but not under anaerobic conditions. These results indicate the unique hydride shift from β-carbon to α-carbon during acid hydrolysis and reveal the mechanism of liberation of arterenone and related compounds from dehydro NADA linked cuticle.
authors.affiliation: Department of Biology, 100 Morrissey Blvd, University of Massachusetts Boston, Boston, MA 02125, USA. manickam.sugumaran@umb.edu
authors.forename: Manickam
authors.initials: M
authors.lastname: Sugumaran
authors.forename: Adal
authors.initials: A
authors.lastname: Abebe
authors.forename: Owen
authors.initials: O
authors.lastname: Oboite
authors.forename: Dong
authors.initials: D
authors.lastname: Zheng
mesh_terms: D000098:Acetophenones / Q000737:chemistry / Q000378:metabolism*; D000825:Animal Structures / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D004175:Diptera / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism*; D007814:Larva / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D013058:Mass Spectrometry; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D000098:Acetophenones; C038699:acetophenone