enzyme activity reduced kinase activity reduced Any variation that results in a decrease in the catalytic phosphorylation activity of a kinase enzyme compared to control. Catalysts are naturally occurring macromolecular substances known as enzymes. Enzymes possess specific binding sites for substrates, and are usually composed wholly or largely of protein (can include an RNA component). Kinases are enzymes capable of phosphorylating their respective substrates. WBPhenotype:0002213 C_elegans_phenotype_ontology