博士 / 國立臺灣大學 / 動物學研究研究所 / 93 / Transglutaminase (TG) is important for blood coagulation and post-translation remodeling of proteins. For characterization of the biological function of TG in shrimp, we isolated a cDNA encoding a novel TG from a shrimp (Penaeus monodon) hemocyte cDNA library. The STG I cDNA consists of an open reading frame of 2271 bp. The deduced protein has 757 amino acid residues, a calculated molecular mass of 84,713 Da and an isoelectric point of 5.56. Neither a typical hydrophobic leader sequence nor a transmembrane domain could be identified from the deduced sequence. Thus, STG I may be a typical cytoplasmic protein. One Arg-Gly-Asp (RGD) motif was identified in STG I. The sequence of STG I was similar to crayfish, other invertebrate and vertebrate TG sequences. Residues critical for enzyme function and calcium binding are conserved between STG I with other members of TG family. High level of STG I mRNA expression was only detected in hematopoietic tissue and high level of protein was existed in circulating hemocytes. Recombinant STG I (rSTG I) exhibited the transamidation activity. The transamidation activity is calcium dependent. rSTG I used clottable protein (CP) as the substrae but lacked coagulation activity. We failed to find out other natural substrates of STG I from tiger shrimp. In vitro, rSTG1 increased hemocyte attachment and spreading dose-dependently. Adhesion of shrimp hemocytes on rSTG I is RGD-dependent. However, when concentration of rSTG I was higher than 60 nM, hemocytes showed highly spread or necrotic morphology. Trypan blue staining showed that the stimulated cells seem to be dead. Further researches are needed to establish the physiological importance and regulatory mechanism of STG I function
| Identifer | oai:union.ndltd.org:TW/093NTU05312031 |
| Date | January 2005 |
| Creators | Chih-Cheng Huang, 黃志成 |
| Contributors | 宋延齡 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 192 |
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