  Based on the recently proposed action for Matrix theory describing the DLCQ M
theory in the maximally supersymmetric pp-wave background, we obtain the
supersymmetry algebra of supercharge density. Using supersymmetry
transformation rules for fermions, we identify BPS states with the central
charges in the supersymmetry algebra, which can be activated only in the large
N limit. They preserve some fraction of supersymmetries and correspond to
rotating transverse membranes and longitudinal five branes.
