A kinase assay using CDK1 kinase showed that phosphorylation of NIPA occurred at a mean rate of 0.494 ± 0.044 pmol phosphate/min in the Arg-363 variant compared with 0.694 ± 0.141 pmol phosphate/min in the His-363 variant, so phosphorylation is occurring significantly slower in the CAD-risk variant of the protein (p = 0.002) (Fig. 1C). Here, ZC3HC1 is linked to coronary artery disorder.