5x met/cys media

[Lisa Imboden]

I'm trying to do a pulse-chase experiment to determine the half-life of 
my protein.  The protocol calls for incubating with met/cys free DMEM, 
followed by incubations with [35S]-labeled met/cys, followed by washing 
with regular media and chasing with media containing 5X met/cys.  I 
can't figure out the best way to make media containinng 5X met/cys.  
I've read that met and cys are both susceptible to oxidation and 
therefore need to be made in degassed water.  I can't find any 
information about how other people have made their 5X met/cys media.  
Any suggestions?