PROTEINS-ESSENTIAL BUILDING BLOCKS OF LIFE

Proteins are macromolecules found in all living things. Proteins are naturally occurring polypeptides composed of monomers called amino acids. Proteins show great diversity such as enzymes, keratin, melanin and so on. The common feature associated with proteins irrespective of their structure is specificity. For instance, haemoglobin and myoglobin specifically binds molecular oxygen, enzymes bind to specific foreign bodies during immunological responses.




Proteins can either be simple or conjugated. Simple proteins are composed of amino acids while conjugated proteins contain other compounds apart from amino acids. Examples of simple proteins are glycine, histidine, phenylalanine, tyrosine and so on while conjugated proteins include glycoproteins and proteoglycans, lipoproteins. Glycoproteins and proteoglycans have carbohydrates as their prosthetic groups while lipoproteins have lipids as their prosthetic groups.




Proteins are known to fulfill diverse biochemical roles. It is also pertinent to note that functions of proteins are understood with respect to how the structure of such proteins allow the specific binding of particular molecules. The following are functions performed by proteins viz; enzymatic activity, transport and storage, mechanical functions, movement, protection and information processing.




Enzymes are known as biological catalysts and proteins.They are capable of enhancing rates of reactions by factors of about 1012. Haemoglobin and myoglobin are transport proteins. They are able to bind specifically to molecular oxygen. Haemoglobin makes oxygen to be readily available to tissues. Ferritin,is a protein that stores iron in various tissues.



Proteins perform structural functions. For instance, collagen provides tensile strength in skin, teeth and bone. Cell membranes and cell organelles are also partly composed of proteins. Movement via the use of muscles is enhanced by the interaction between protein filaments actin and myosin with myosin facilitating the enzymatic process that converts chemical energy of ATP into mechanical energy.




Antibodies and immunoglobulins are proteins found in mammals and they confer immunity by eliciting immunological responses. They also interact with complement to phagoticize and lyse foreign cells leading to their destruction. Signal transduction can be produced from hormones and light intensity detected by specific protein receptors which are capable of transfering the signal to the target cells via the process of biosignalling.For instance, in the biochemistry of vision, rhodopsin,a visual protein located in the retinal photoreceptors called rods and cones play an invaluable role in vision.



The role of proteins as building blocks in living organisms cannot be overemphasized. Hence, the need to consume proteinous foods should be encouraged.