Function: Human Salivary Amylase, a type of alpha-amylase, is secreted in your salvia and is responsible for hydrolyzing alpha-bonds of large alpha linked polysaccharides such as starch. Eventually after chewing, the starch is broken down into polysaccharides composed of glucose and maltose. It also plays a role in the colonization of bacteria that contribute to early dental plaque formation.
Salivary amylase works best in a neutral pH (5.6-6.9) at normal body temperature around 37° C. Surprisingly enough, Salivary amylase becomes inactive when is reaches the stomach by the acidic environment.
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| Biological Assembly Image for 1SMD HUMAN SALIVARY AMYLASE http://www.rcsb.org/pdb/explore/explore.do?structureId=1smd |
Structure: Salivary alpha-amylase has 496 residues, one Ca+ ion, one Cl- ion, and 170 water molecules. This multidomain protein has 3 domain (A,B, and C). Domain A contains 8 (beta/alpha) barrel structures whereas domain B has no definite secondary structures. Domain C has Greek key-barrel structures made of beta-pleated sheets. The placement of the calcium and chloride ions, as well as the residues, plays a role in the substrate-binding mechanism. Salivary amylase also has a suitable place for binding to tooth enamel surfaces where is can become a place of attachment for bacteria that live in the oral cavity. For this reason, it is essential for people to brush their teeth regularly to prevent plaque buildup which can then leads to the formation of dental caries.
References/ Bibliography:
Ramasubbu N, Paloth V, Luo Y, Brayer GD, Levine MJ. (1996). Structure of human salivary alpha amylase at 1.6 A resolution: implications for its role in the oral cavity. Acta Crystallogr D Biol Crystallogr. 1996 May 1 ;52(Pt 3): 435-46.
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