P-type ATPases Essay example -- Chemical Biology, Biochemistry

Describe the mechanism of P-type ATPases select one P-type ATPase and examine how its physiological role has been investigated.The P-type ATPases are a large family of membrane enzymes, with 476 unalike subtypes categorised in the Swiss-Prot protein in attaination database. The P-type or E1-E2 ATPases were first discovered and categorised by Jens Christian Skou, a Danish physician-turned-physiologist in 1957. Skou discovered the Na+/K+ ATPase, and later shared half of the 1997 Nobel Prize for Chemistry in reward for his work (Skou 1997).As mentioned above, the P-type ATPases have a broad range of interventions, for example, the use of the digitalis toxin in the treatment of heart failure (Rang et al. 2007). There are 5 broad classes of P-type ATPase, and numerable sub-classes. Human ATP-ases are primarily grouped in classed I, II and IV, with group III consisting of bacterial enzymes, and group V largely unclassified (Stokes and Green 2003). An especially important role of an ATPas e in humans is the transport of atomic number 11 and potassium ions across the cell membrane. It is this Na+/K+ ATPase that J.C Skou discovered, and worked on for most of his academic career (Skou 1997). The fundamental basis of the P-type ATPases ability to function is its capacity to form 2 conformational states, E1 and E2. Both of these states are ion-binding, one allowing intramembrane ion binding, and the other with an extramembrane ion binding site. The Na+/K+ ATPase is an anti-porter, transporting Na+ ions out of the cell, and K+ ions into the cell, at a 32 ratio (NaK), against the concentration gradient (Lehninger et al. 2000). The process of transporting ions across the membrane is a 4 step mechanism, as shown in figure 1. Firstly, 3 N... ... a thespian in the Active Transport of Sodium and Potassium in the Human Erythrocyte. Journal of Biological Chemistry 235(6), pp. 1796-1802.Rang, H. P. et al. 2007. Rang and Dales pharmacology. 6th ed. Edinburgh Churchill Livingston e/Elsevier, pp. xiii, 829 p.Shull, G. E. et al. 1985. Amino-acid sequence of the catalytic subunit of the (Na+ + K+)ATPase deduced from a complementary DNA. Nature 316(6030), pp. 691-695.Skou, J. C. 1997. The Nobel Prizes 1997. Stockholm Nobel Foundation.Skou, J. C. 2004. The Identification of the Sodium Pump. Bioscience Reports 24(4), pp. 436-451.Skou, J. C. and Esmann, M. 1992. The Na,K-ATPase. Journal of Bioenergetics and Biomembranes 24(3), pp. 249-261.Stokes, D. L. and Green, N. M. 2003. STRUCTURE AND FUNCTION OF THE CALCIUM PUMP. Annual Review of Biophysics and Biomolecular Structure 32(1), pp. 445-468.