卫氏并殖吸虫
酪氨酸酶
氧化酶试验
生物
羟基化
生物化学
互补DNA
酪氨酸
酶
基因
蠕虫
动物
肺吸虫病
作者
Young-An Bae,S.-H. Kim,Chuljin Ahn,J.-G. Kim,Yoon Kong
出处
期刊:Parasitology
[Cambridge University Press]
日期:2015-01-26
卷期号:142 (6): 807-815
被引量:5
标识
DOI:10.1017/s0031182014001942
摘要
SUMMARY Trematode tyrosinases (TYRs) play a major role in the tanning process during eggshell formation. We investigated the molecular and biochemical features of Paragonimus westermani TYR (PwTYR). The PwTYR cDNA was composed of 1568-bp encompassing a 1422-bp-long open reading frame (474-amino acid polypeptide). A strong phylogenetic relationship with Platyhelminthes and Deuterostomian orthologues was evident. The recombinant PwTYR expressed in prokaryotic cells promptly oxidized diphenol substrates, with a preferential affinity toward ortho -positioned hydroxyl groups. It demonstrated fairly weak activity for monophenol compounds. Diphenol oxidase activity was augmented with an increase of pH from 5·0 to 8·0, while monophenol oxidase activity was highest at an acidic pH and gradually decreased as pH increased. Transcription profile of PwTYR was temporally upregulated along with worm development. PwTYR was specifically localized in vitellocytes and eggs. The results suggested that conversion of tyrosine to L-dihydroxyphenylalanine by PwTYR monophenol oxidase activity might be rate-limiting step during the sclerotization process of P. westermani eggs. The pH-dependent pattern of monophenol and diphenol oxidase activity further proposes that the initial hydroxylation might slowly but steadily progress in acidic secreted vesicles of vitellocytes and the second oxidation process might be rapidly accelerated by neural or weak alkaline pH environments within the ootype.
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