Answer:
One 30 kD subunit: Three 50 kD subunits
Step-by-step explanation:
SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis) is a variant of electrophoresis, which is used in the analysis of molecules (proteins) on the basis os size.
Sodium dodecyl sulfate (SDS) is an ionic detergent that denatures proteins and make them uniformly charged.
In this process proteins are separated on the basis of size , not on the basis of charge, and recognized by band size.
After running a SDS-PAGE assay on an unknown protein with molecular size 180 kD proteins show two bands on the basis of size, these are of 30 kD subunit, and three 50 kD subunits,