Nature of the subunits of the 6-phosphofructo-1-kinase isoenzymes from rat tissues.

The nature of the PFK (6-phosphofructo-1-kinase) isoenzymes in many rat tissues was examined by immunological and chromatographic techniques and by measurement of their subunit compositions. It was revealed that, except for diaphragm and skeletal muscle, these complex isoenzymic populations contained different amounts of the three subunit types and were nearly tissue-specific. Apparently this tissue specificity is due to different concentrations of the tetramers, which in turn are controlled by the types and amounts of each subunit that are available to associate randomly.