CHAPTER 20: Unit 9. Enzyme and Cofactors and Vitamins

Enzymes are active when the polypeptide chains are folded. Some enzymes need cofactors to catalyze specific reactions.The cofactors are metal ions or small molecules. A small amount of these cofactors are needed to facilitate the enzyme catalyzed reaction.

Examples of these cofactors are:Metal ions such as Cu2+, Fe3+, Zn2+, Mg2+, Mn2+ and Ni2+.Organic molecules which include fat soluble vitamins as well as water soluble vitamins (coenzymes)

The figure below illustrates the types of cofactors:

Reference: https://studylib.net/doc/9207266/enzyme-cofactors

1.  Metal ions cofactors:Example of metal cofactors is Zinc ion (Zn2+) is given the figure below:

Reference: https://www.slideshare.net/nourtamim/catalysis-mechanisms

Example of metal cofactors is Nickel ion (Ni2+) is given the figure below:

Reference: https://www.researchgate.net/figure/The-binding-mode-of-complex-1-in-the-active-site-of-urease-enzyme-from-Bacillus_fig4_236204262

The table below illustrates the metal ions cofactors:

Reference: https://slideplayer.com/slide/8060701/

1.  Organic molecules which include fat soluble vitamins as well as water soluble vitamins (coenzymes)Vitamin are considered as cofactors and they are also called coenzymes. They are not produced in the human body, but they are very essential in small amount for the human health and growth. They are not amino acids

There are two types of vitamins

a.) Water – Soluble Vitamins (coenzymes)Water – Soluble Vitamins have polar groups such -OH and -COOH. They are easily destroyed by higher temperatures, light and radiation. Also, the presence of oxygen can destroy them. Examples of water – soluble vitamins are vitamins B1 (thiamine) and B2 (riboflavin) etc. (see table below). Water – soluble vitamin are called coenzymes.

The table below lists some water – soluble vitamins:

Reference: https://microbenotes.com/water-soluble-vitamins-b-complex-and-c/

The decencies of some water-soluble are listed below:

Reference: https://www.pinterest.com/pin/569564684118148681/

Water – soluble structures are given below:

Reference: https://www.researchgate.net/figure/Chemical-structure-of-water-soluble-vitamins_fig3_251666334

The video below illustrates the water – soluble vitamin functions:

b.) Water – Insoluble VitaminsWater – Insoluble Vitamins are also called fat soluble – vitamins.Examples of fat – soluble vitamins are vitamins A, D, E and K.Fat – soluble vitamins are not considered coenzymes, but they are very important in the health and the growth of human body. They have important functions in vision, formation of bones and blood clotting prevention and prevention from, oxidation.Fat – soluble vitamins can absorb free radical such as. OH, NO. and O2.,, resulted from oxidation process. Free radicals can react easily and cause mutation of the cells and thus tumors and later cancer diseases can develop,The figure below illustrates some vegetables that contain fat – soluble vitamins:

Reference: https://loveonetoday.com/nutrition/avocados-fat-soluble-vitamins/

Examples of fat – soluble vitamins are given in the table below:

Reference: https://www.healthyarea.org/fat-soluble-vitamins-ultimate-guides-fat-soluble-vitamins/

Water – insoluble (fat – soluble) structures are given below:

Reference:https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Lipids/Properties_and_Classification_of_Lipids/Lipid_Soluble_Vitamins

The video below illustrates the fat – soluble (water – insoluble) vitamins: