Updated project metadata. Protein hydroxylases are oxygen and alpha-ketoglutarate-dependent enzymes that catalyze hydroxylation of amino acids such as proline, thus linking oxygen and metabolism to enzymatic activity. Prolyl hydroxylation is a dynamic post-translational modification that regulates protein stability and protein-protein interactions; however, the extent of this modification is largely uncharacterized. The goals of this study are to investigate the biological consequences of prolyl hydroxylation and to identify new targets which undergo prolyl hydroxylation in human cardiomyocytes.