A vote on the confirmation of former state Republican Party Chairman Tirso Del Junco as a UC regent was postoned by the state Senate Rules Committee at the request of Sens. Alfred E. Alquist (D-San Jose) and John Garamendi (D-Walnut Grove). Garamendi questioned Del Junco's commitment to maintaining the University of California as a world-class university. A spokesman for Alquist said the senator wants to determine whether Del Junco has shown a GOP bias since he was appointed. Del Junco, 60, a Pasadena surgeon, was appointed to the board last September by Gov. George Deukmejian. A second Deukmejian appointee to the board, Leo S. Kolligian, 68, a Fresno attorney, was recommended by the committee for confirmation.