Introduction

Abstract

About one-third of all known enzymes require metal ions in one way or another. Some enzymes have metal ions strongly bound to their own protein structures; these are called metalloenzymes. Others require added metal ions as a co-factor. The studies on metalloenzymes and metal-activated enzymes constitute a major portion of bio-inorganic chemistry. Proteins containing metal ions as an active factor are called metalloproteins. They function mostly as oxygen carriers, electron carriers and metal carriers. The studies on metalloproteins are not less important than those on metalloenzymes. Some of the important metalloproteins, metalloenzymes and metal-activated enzymes are listed in Table VII.1.