(b) For each MMP species in Figure 2, the gel band area per µg of protein was determined for both homogenates and supernatants and the percentage of species bound was calculated using (1). HMW2 was observed to be tightly bound to the membranous or insoluble extracellular component in brain tissue. The amount of HMW1 and pro-MMP9 bound was significantly reduced in AD. Control donors: numbers 1–4; AD donors: numbers 5–7, 9. ^∗p < 0.05.

MMP species	Percentage of bound MMP species (mean ± SD)
	Control	AD
HMW2	93.8 ± 5.0	90.3 ± 1.3
HMW1	47.3 ± 24	13.3 ± 14.3∗
Pro-MMP9	55.5 ± 11.8	28.5 ± 15.4∗
Pro-MMP2	0	0