In enzymology, an ubiquitin-calmodulin ligase (EC 6.3.2.21) is an enzyme that catalyzes the chemical reaction
n ATP + calmodulin + n ubiquitin
⇌
n AMP + n diphosphate + (ubiquitin)n-calmodulin
The 3 substrates of this enzyme are ATP, calmodulin, and ubiquitin, whereas its 3 products are AMP, diphosphate, and (ubiquitin)n-calmodulin.
This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D-amino-acid ligases (peptide synthases). The systematic name of this enzyme class is calmodulin:ubiquitin ligase (AMP-forming). Other names in common use include ubiquityl-calmodulin synthase, ubiquitin-calmodulin synthetase, ubiquityl-calmodulin synthetase, and uCaM-synthetase.