Vol. 181, No. 3, 1991 BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS December 31, 1991 Pages 927-932 ISOLATION AND IDENTIFICATION OF A NEW DIURETIC PEPTIDE FROM THE TOBACCO HORNWORM, MANDUCA SEXTA Michael B. Blackburn’, Timothy G. Kingan2, Wanda Bodna?, Jeffrey Shabanowitg, Donald F. Hun+, Tomas Kempe41 Renee M. Wagner’, Ashok K. Raina2, Michael E. Schnee6, and Michael C. Mals ’ Department of Entomology, University of Maryland, College Park, MD 20742 2 Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705 3 Department of Chemistry, University of Virginia, Charlottesville, VA 22901 4 Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742 5 Livestock Insect Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705 6 Du Pont Agricultural Products, Stine Haskell Research Center, Newark, DE 19714 7 Center for Agricultural Biotechnology, Maryland Biotechnology Institute, University of Maryland, College Park, MD 20742 Received November 9, 1991 A 30-amino acid diuretic peptide was isolated from the corpora cardiaca-corpora allata complexes and, separately, from medial neurosecretory cells of the S Manduca sexta. The peptide was found to have the following sequence, B hingid moth, etermined by automated Edman de radation and mass spectrometry: SFSVNPAVDILQHRYMEKV AQNNRNFLNRV-N I-f 2. We have named the peptide Mas-DP II. The peptide was synthesized and shown to possess diuretic activity in decapitated moths. Mas-DP II is related by sequence homology to a 41-amino acid diuretic peptide identified previously from M. sexta, and it belongs to the family of corticotropin releasing factor-like peptides. 0 1991 Academic Press, Inc. Insects, which have a large surface area in relation to their weight, must generally conserve water. At times, however, such as after a large fluid meal, insects must eliminate excess water. This type of diuretic response is particularly well documented among blood- aTo whom reprint requests should be addressed at Department of Entomology, University of Maryland, College Park, MD 20742. Abbreviations: CC-CA, corpora cardiaca-corpora allata; CRF, corticotropin releasing factor; ESMS, electrospray ionization tandem mass spectrometry; QFTMS, quadrupole Fourier transform mass spectrometry; HPLC, high performance liquid chromatography; mAU, milliabsorbance units; (M + H)+, protonated molecular ion; TFA, trifluoroacetic acid; UV, ultraviolet. C@O6-291x191 $1.50 927 Copyright 0 1991 by Academic Press, Inc. All rights of reproduction in any form reserved.