Janssen I, Koolman J, Konopinska D, Bartosz-Bechowski H, Schoofs L, De Loof A
Laboratory for Developmental Physiology & Molecular Biology, Zoological Institute K. U. Leuven, Belgium.
Peptides. 1998;19(4):627-34. doi: 10.1016/s0196-9781(97)00478-6.
The trypsin modulating oostatic factor from the gray fleshfly Neobellieria bullata (Neb-TMOF) is released from the ovary at the end of vitellogenesis and inhibits trypsin biosynthesis in the midgut. This inhibition indirectly results in an arrest of oocyte growth. Additional experiments with N. bullata were performed to characterize its trypsin modulating and oostatic properties in more detail. After suspending the peptide in wheat germ oil, the threshold dose for oostatic activity was lowered one thousand times (2.10(-5) in oil versus 2.10(-2) pmoles per fly in Ringer). By use of the Neobellieria trypsin biosynthesis assay, 17 analogs of the hexapeptide were tested for inhibitory activity. The following structural elements were demonstrated to be critical for biological activity: the alcohol function at position 3 (Thr residue); a positively charged basic group at the C terminus (His residue); and the Asn side chain at positions 1 and 4.
来自灰肉蝇（Neobellieria bullata）的胰蛋白酶调节卵发育抑制因子（Neb - TMOF）在卵黄发生末期从卵巢释放，并抑制中肠中胰蛋白酶的生物合成。这种抑制间接导致卵母细胞生长停滞。对灰肉蝇进行了更多实验，以更详细地表征其胰蛋白酶调节和卵发育抑制特性。将该肽悬浮于麦芽胚油中后，卵发育抑制活性的阈值剂量降低了一千倍（在油中为2×10⁻⁵，而在林格氏液中为每只果蝇2×10⁻²皮摩尔）。通过使用灰肉蝇胰蛋白酶生物合成测定法，对该六肽的17种类似物进行了抑制活性测试。已证明以下结构元件对生物活性至关重要：第3位的醇官能团（苏氨酸残基）；C端带正电荷的碱性基团（组氨酸残基）；以及第1和4位的天冬酰胺侧链。
