1× MAS buffer without BSA (can be made prior to the assay and stored at 4°C for 3 months)

Reagent	Final concentration	Amount
Mannitol	220 mM	20.04 g
Sucrose	70 mM	11.98 g
Potassium Monophosphate (KH2PO4)	10 mM	0.68 g
Magnesium Chloride (MgCl2, 1M)	5 mM	2.5 mL
EGTA (250mM stock solution; pH to 8.0 with KOH)	1 mM	2 mL
HEPES (1M)	2 mM	1 mL
KOH (1M)	n/a	to pH 7.2
Tissue culture grade water	n/a	fill to 500 mL
Total	n/a	500 mL