A theoretical analysis of steady-state kinetics of the translation system involving a number of different mRNAs is presented. The specific rates of initiations are shown to play the key role in regulation of translation of different mRNAs. Conditions under which the specific rates of initiation become the functions of the specific rates of elongator codons reading and the elongator codons sequence are analyzed. Such conditions correspond to the situation when one ribosome of polyribosomal complex catches up with another ribosome and stumbles upon it during the mRNA translation. A conclusion is drawn on great significance of the polyribosomal organization of translation apparatus in the regulation of rates and ratio of individual proteins biosynthesis.