Flow cytometric analysis of gelatinase B (MMP‐9) activity using immobilized fluorescent substrate on microspheres

connective tissues is determined by the delicate balance between the synthesis and resorption of extracellular matrix (ECM) molecules. Breakdown of this balance is associated with a variety of pathological con- ditions, such as joint degeneration in rheumatoid arthritis, demyelination in multiple sclerosis, and dissemination of malignant tumors (8,13,19,20). Matrix metalloprotein- ases (MMPs) are thought to play a crucial role in ECM degradation. Their ability to degrade collagen and other components