Identification of novel fish sialidase genes responsible for KDN-cleaving activity
Identification of novel fish sialidase genes responsible for KDN-cleaving activity
复制标题
负责 KDN 裂解活性的新型鱼类唾液酸酶基因的鉴定
DOI：
10.1007/s10719-020-09948-6
复制
发表时间：
2020
影响因子：
3
通讯作者：
Wakata Ryuta
中科院分区：
文献类型：
--
作者：
Shiozaki Kazuhiro;Uezono Keiya;Hirai Go;Honda Akinobu;Minoda Masaya;Wakata Ryuta
2-酮-3-脱氧-D-甘油-D-半乳糖-壬糖酸（KDN）是脊椎动物（如人类癌细胞、大鼠肝脏和鱼类组织）中检测到的唾液酸的次要组分。虽然已在虹鳟鱼中检测到KDN-cleaving sialidase（KDN-sialidase）的酶活性，但尚未在脊椎动物中确定负责其表达的基因。我们评估唾液酸酶在人类和各种鱼类的KN裂解活性，使用人工底物，甲基伞形酮-KDN（MU-KDN）。测试的四种人唾液酸酶（NEU 1、NEU 2、NEU 3和NEU 4）不水解MU-KDN。虽然大多数鱼类Neu 1 s表现出可忽略不计的KDN-sialidase活性，但来自尼罗罗非鱼和Neu 1的一种partial，墨西哥丽鱼的两种Neu 1b唾液酸酶表现出强有力的KDN-sialidase活性。此外，O.尼罗罗非鱼和青鳉Neu 3a显示出极高的KDN-sialidase活性，而斑马鱼Neu3.1显示出中等活性，而其它Neu 3蛋白显示出很低的活性。在鱼中测试的所有Neu 4唾液酸酶分别以相等的潜力从MU-KDN和MU-Neu 5Ac切割KDN和Neu 5Ac。据我们所知，这是第一个报告，以确定在脊椎动物中的KN-唾液酸酶基因，我们认为，KN-唾液酸酶活性可能是保守的鱼类Neu 4s。
2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN) is a minor component of sialic acids detected in vertebrates, such as human cancer cells, rat liver, and fish tissues. Although the enzyme activity of KDN-cleaving sialidase (KDN-sialidase) has been detected in rainbow trout, the gene responsible for its expression has not been identified in vertebrates. We evaluated sialidases in human and various fish for their KDN-cleaving activity using an artificial substrate, methylumbelliferyl-KDN (MU-KDN). Four of the human sialidases tested (NEU1, NEU2, NEU3, and NEU4) did not hydrolyze MU-KDN. Although most fish Neu1s showed negligible KDN-sialidase activity, two Neu1b sialidases fromOreochromis niloticusandAstyanax mexicanus, a paralog of Neu1, exhibited a potent KDN-sialidase activity. Further,O. niloticusandOryzias latipesNeu3a exhibited a drastically high KDN-sialidase activity, whileDanio rerioNeu3.1 showed moderate activities and other Neu3 proteins exhibited little activity. All the Neu4 sialidases tested in fish cleaved KDN and Neu5Ac from MU-KDN and MU-Neu5Ac, respectively, with equivalent potential. To our knowledge, this is the first report to identify KDN-sialidase genes in vertebrates and we believe that KDN-sialidase activity could be conserved among fish Neu4s.