1. The enzyme can be obtained in both apoenzyme and holoenzyme forms. 2. Crystallographic studies have helped elucidate the apoenzyme structure of phosphopentose epimerase. 3. Cytochrome c oxidase ( COX ), the terminal component of the apoenzyme . 4. However, the apoenzyme without copper is unstable. 5. The apoenzyme form, lacking the zinc cofactor, has a molecular weight of 382815.4 g / mol. 6. This protein has also been used in fluorescent sensing either simply as an apoenzyme or as an as a holoenzyme. 7. An inactive enzyme without the cofactor is called an apoenzyme , while the complete enzyme with cofactor is called a holoenzyme. 8. A mutant ( D58A, in one of the active-site loops ) was crystallized as an apoenzyme also ( ). 9. In this system, the inactive form ( the apoenzyme ) becomes the active form ( the holoenzyme ) when the coenzyme binds. 10. Enzymes that require a cofactor but do not have one bound are called " apoenzymes " or " apoproteins ".
