2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/184383Following hep-th/0309238 relating the matrix string theory to the light-cone superstring field theory, we write down two supercharges in the matrix string theory explicitly. After checking the supersymmetry algebra at the leading order, we proceed to discuss higher-order contact terms.17 pages, no figures, v2: eq. (5.1) and related appendices corrected, v3: final version to appear in JHEPHigh Energy Physics - Theorytext