Distribution of Chitinolytic Enzymes in the Organs and cDNA Cloning of Chitinase Isozymes from the Liver of Golden Cuttlefish <i>Sepia esculenta</i>

• 作者: Hideto Fukushima Hiromi Kakizaki Masahiro Matsumiya Ryo Nishino
• 来源期刊: 生命科学与技术进展(英文)
• 学科: 医学
• 关键词: Chitinolytic Enzyme CHITINASE Distribution cDNA Cloning GOLDEN CUTTLEFISH SEPIA esculenta
• 年，卷（期）: smkxyjsjzyw_2017,（10）
• 页码范围: 361-377
• 页数: 17页
• 分类号: R73

摘要

The distribution of chitinolytic enzymes in eight organs of the golden cuttlefish Sepia esculenta was determined. Chitinase activity (activity of endo-type chitinolytic enzyme) was measured using pNP-(GlcNAc)n (n = 2, 3) as substrates, with high activity detected in the liver, posterior salivary gland, and stomach. β-N-acetylhexosaminidase (Hex) activity (activity of exo-type chitinolytic enzyme) was determined using pNP-(GlcNAc) as a substrate, and high activity was observed in six organs, including the liver, branchial heart, posterior salivary gland, and stomach. In addition, two chitin-binding proteins (CBP-A, CBP-B) were isolated from the liver using a chitin affinity column. Two full-length cDNAs (SeChi-1: 1484 bp;SeChi-2: 1748 bp) encoding chitinases were obtained from the liver of S. esculenta. SeChi-1 contained a 1377-bp open reading frame (ORF) encoding 459 amino acids, and SeChi-2 contained a 1656-bp ORF encoding 552 amino acids. Domain structures predicted from the deduced amino acid sequences of SeChi-1 and SeChi-2 (SeChi-1, SeChi-2) contained signal peptides, a GH Family 18 catalytic domain, one chitin binding domain (CBD) in SeChi-1, and two CBDs in SeChi-2. Proteome analysis revealed that 125 peptide residues of CBP-A were present in SeChi-1, and 116 peptide residues of CBP-B were present in SeChi-2. Organ expression analysis revealed that SeChi-1 and SeChi-2 were expressed only in the liver of S. esculenta. Phylogenetic analysis of SeChi-1, SeChi-2, and GH family 18 chitinases revealed that SeChi-2 belongs to a group of previously reported squid chitinases, while SeChi-1 does not belong to any previously reported group of mollusk chitinases.