|Thompson, Kenneth - Kentucky State University|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/1/2013
Publication Date: 7/17/2015
Citation: Webster, C.D., Thompson, K.R. 2015. Proteins and Amino Acids. Webster, C.D., Thompson, K.R., editors.Dietary Nutrients, Additives, and Fish Health.Hobokon, NJ: Wiley Blackwell. p. 25-45.
Technical Abstract: Proteins are the most abundant substances in living organisms and cells. All proteins are constructed from the same twenty amino acids that are linked together by covalent bonds. Shorter chains of two or more amino acids can be linked by covalent bonds to form polypeptides. There are twenty amino acids from which organisms can synthesize a wide array of biologically-important products such as enzymes, hormones, feathers, scales, and antibiotics. Proteins differ from one another due to their own unique sequence of amino acid units. Since there are many different proteins in an organism, they have many different biological functions. Enzymes are highly-specialized proteins that are responsible for catalytic activity. Transport proteins found in blood plasma bind/carry specific molecules or ions from one organ to another. Hemoglobin is one such protein that carries oxygen to tissues in an organism. Nutrient proteins are exemplified by casein; storage proteins are found in the seeds of plants; contractile proteins allow an organism to change shape or to locomote and move and are represented by actin and myosin found in skeletal muscle; motile proteins, such as tubulin, are components of cilia and flagella which allow for movement; structural proteins serve to strengthen biological tissues and cells and are represented by collagen, elastin, and keratin; regulatory proteins assist in cellular or physiological activities and are represented by hormones; and proteins can serve to protect the organism against infection or injury and are represented by immunoglobulins. Immunity is the ability of an organism to resist attack from a pathogen. Generally, fish have an immune system that has shorter response times, is less specific, has weaker recognition memory, and has a smaller immunoglobulin array than humans. Further, the mucus of fish has a more prominent response in defending the organism from pathogens. While fish have a humoral response and a cellular response, as in mammals, shrimp do not have a specific response and rely on a rudimentary system that includes phagocytosis and the use of lectins. This chapter will look at the influence proteins and amino acids have on the immune system of fish and shrimp.