isoform

noun

1. Any of several different forms of the same protein, arising from either single nucleotide polymorphisms, differential splicing of mRNA, or post-translational modifications (e.g. sulfation, glycosylation, etc.)

   “Intriguingly, the rat C1b isoform of the calcitonin receptor (CTR) (see Section VI-B) has very little interaction with the thyroidally derived form of calcitonin.”