We evaluate the contribution of a class of higher-twist operators to the lowest moment of the structure functions, by computing appropriate matrix elements of six four-fermion operators in the quenched approximation. Their perturbative renormalization constants and mixing coefficients are calculated in the 't Hooft-Veltman scheme of dimensional regularization, using codes written in the algebraic manipulation computer language FORM. (orig.)11 refs.Available from TIB Hannover: RA 2999(99-116) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman