## 1 Introduction  
_Eurygaster integriceps_ Puton, commonly known as sumn pest, belongs to the order Hemiptera and family Scutelleridae. This true bug is considered a major pest of wheat crops in Northern Africa, the Middle East and Eastern Europe. In addition to direct reduction in wheat crops during the life cycle of the bug, the sumn pest also injects saliva containing hydrolytic and proteolytic enzymes into the grains during feeding. The mechanism of injection is most likely similar to that shown for a closely related bug, brown marmorated stink bug, _Halyomorpha halys_ (Hemiptera: Pentatomidae), which secretes its proteases in the watery saliva through a styled in the beak [1]. The salivary glutenase, characterized as a prolyl endoprotease (spPEP) by [PERSON] _et al._[2], assists in penetration and pre-oral digestion of the grain contents by degrading the high molecular weight gluten proteins of the wheat. The spPEP remains in the grain after the bugs have finished feeding and continue to cause extensive damage to the gluten proteins when the grain is milled and used as dough. The degradation of the gluten causes bread made from such dough to be weak, sticky and to have reduced volume and an unusually heavy texture [3,4]. The dough does not rise in the oven and often burns. As little as 2%-5% sumn pest-contaminated grains render the whole lot unacceptable for baking purposes [5,6]. [PERSON] _et al._[2] showed the spPEP to be a serine protease through inhibition by phenylmethylsulfonyl fluoride (PMSF) and, specifically, a prolyl endoprotease, which cleaved peptide bonds at the carboxyl terminal side of the GlyPro-pNA substrate. The enzyme was partially purified by [PERSON] _et al._[2], exhibiting a Km of 65.3 \(\pm\) 1.8 \(\upmu\)M for the GlyPro-pNA substrate at pH 8, 22 \({}^{\circ}\)C, with maximum activity between pH 8-10 and 25 \({}^{\circ}\)C-35 \({}^{\circ}\)C in 25 mM ethanolamine buffer. The turnover number could not be determined by [PERSON], because the enzyme was not purified to homogeneity. A recombinant form of the enzyme responsible for gluten degradation is required to determine environmentally safe inhibitors to reduce crop losses. The spPEP is unique, because its natural substrates are large gluten proteins; [PERSON] _et al._[7] showed the enzyme to preferentially hydrolyze high molecular weight glutenins that are as large as 140 kD. [PERSON] [8] and [PERSON] [2] showed a general specificity for whole gluten containing both the high and low molecular weight glutenins and gliadins, as well as specificity for the dipeptide GPpNA. The primary focus of this study was to clone the full transcript of the spPEP and produce an active recombinant prolyl endoprotease from the sumn pest. Prior to submission of the nucleic acid sequence obtained from this study, the only nucleotide sequence reported for true bugs in the National Center for Biotechnology Information (NCBI) was amylase for _Eurygaster integriceps_; therefore, degenerate primers were designed based on known insect PEP sequences to probe cDNA from each of the life stages of _Eurygaster integriceps_. The cDNA from three different life stages of the sumn pest was constructed with only the adult sumn pest expressing the mRNA for the spPEP. The 5' and 3' untranslated regions of the transcript were analyzed for possible transcription factor binding sites and secondary structure motifs that might be used for translational control for future studies to determine mechanisms of inhibition of the enzyme through either a biological pesticide or the use of transgenic wheat. Inhibitors must be specific to the sumn pest due to human consumption of the wheat; therefore, knowing the complete sequence of the spPEP transcript and comparing it to others, including that of mammals, is important for specifically targeting the spPEP. A phylogenetic comparison of the spPEP amino acid sequences to other known PEPs places the spPEP on a branch with _Daphnia pulex_ separate from other known insects and several nodes distant from mammalian PEPs.