Probable FAD-dependent oxidoreductase; involved in the cellular oxidative stress response (By similarity). Required for normal sarcomere structure and muscle fiber integrity (PubMed:27745833). Binds 1 FAD per subunit. Morpholino-injected embryos show severe disruption of the musculature with fragmentation of the muscle fibers, altered sarcomeric structure, loss of fiber integrity and accumulation of actin at the myosepta (PubMed:27745833). Disintegration of the myofibrils with mitochondrial infiltration of the resulting space, loss of Z-disk structures, and electron dense, nemaline-like bodies are observed by electron microscopy (PubMed:27745833). Belongs to the class-I pyridine nucleotide-disulfide oxidoreductase family. PYROXD1 subfamily.