Abstract: 【Aim】 The expression profile of gene encoding pyridoxine phosphate oxidase (PNPO), which is a key enzyme related to VB₆ metabolism, was analyzed in different developmental stages and tissues of the 5th instar larvae of Bombyx mori. 【Methods】 The recombinant plasmid pET-22b(+)-PNPO was transformed to Escherichia coli Rosetta for induction, expression and purification of PNPO, and then the polyclonal antibody was prepared. The expression profile of PNPO gene was analyzed by Real-time PCR and Western blot, respectively. 【Results】 The highest translation level of PNPO gene was found in the 5th instar larvae. The transcription level in tissues of 5th instar larvae was in sequence of testis＞head＞midgut＞Malpighian tubules＞ovary＞cuticle＞fat body＞silk glands. However, the highest translation level was found in testis, and then was in head, midgut, and malpighian tubules, respectively. 【Conclusion】 The expression profile PNPO gene in B. mori has been defined by this study.

Key words: Bombyx mori, pyridoxine 5′-phosphate oxidase, Western blot, real-time PCR, expression profile