Abstract
The anomalous nuclear enhancement of inclusive spectra at large transverse momentum in high energy protonnucleus collisions is investigated in the framework of the nuclear parton model, especially by taking account of the interaction between the partons of the incident proton and the "collective" partons of the multiquark clusters within the nucleus. The absolute normalization of the parton distribution functions for the multiquark clusters is treated carefully, guided by the quark number and momentum sum rules.