A derivative of L-proline with diverse biological activities; induces misfolding of proteins and reduces the extracellular localization of collagen; inhibits growth of 450.1 murine mammary cancer cells in vitro (IC50 = 7.6 UG/ml) but is inactive in a 450.1 murine model of mammary cancer at 12.5-200 mg/kg per twice per day; teratogenic to, and disrupts skeletal development in, hamster fetuses when administered to pregnant hamsters at 300 mg/kg on gestational day 11