mAcon1 and mAcon2, encoding mitochondrial aconitases, are paralogs: mAcon1 is expressed ubiquitously whereas mAcon2 has a testis-specific expression pattern.

Both proteins encoded by Irp-1A and Irp-1B possess aconitase activity, though only the Irp-1A protein can bind to iron-responsive elements in target mRNAs and therefore functions as an iron-regulatory protein (FBrf0195255).