Prenylcysteine oxidase that cleaves the thioether bond of prenyl-L-cysteines, such as farnesylcysteine and geranylgeranylcysteine (PubMed:10585463, PubMed:11078725, PubMed:12186880). Only active against free prenylcysteines and not prenylcysteine residues within prenylated proteins or peptides (By similarity). Involved in the final step in the degradation of prenylated proteins, by degrading prenylcysteines after the protein has been degraded (PubMed:10585463). an S-prenyl-L-cysteine + H2O + O2 = a prenal + H2O2 + L-cysteine H2O + O2 + S-(2E,6E)-farnesyl-L-cysteine = (2E,6E)-farnesal + H2O2 + L-cysteine [(2E,6E,10E)-geranylgeranyl]-L-cysteine + H2O + O2 = (2E,6E,10E)-geranylgeranial + H2O2 + L-cysteine kcat is 8000 sec(-1) for free farnesylcysteine. Widely expressed. Belongs to the prenylcysteine oxidase family. Was originally thought to be a lyase and was therefore termed prenylcysteine lyase.