ABSTRACT
In humans, L-ascorbic acid (AA) is essential for life (which is why it is called a vitamin) by virtue of its antioxidant properties, which protect cells against oxidative stress (Padayatty et al., 2003). AA deciency is termed scurvy (Wilson, 1975). James Lind, in 1747, was the rst to conclude that eating fruits could prevent scurvy. During the eighteenth and nineteenth centuries, foods able to prevent scurvy were termed antiscorbutic, although the chemical principle was not identied. Albert
16.1 Introduction .................................................................................................. 257 16.2 Functions of Ascorbic Acid .......................................................................... 258
16.2.1 Biochemical Functions ..................................................................... 258 16.2.2 Ascorbic Acid and Development ...................................................... 259
16.3 Ascorbic Acid Transport, Transporting Proteins, and Receptors ................. 259 16.3.1 Passive Transport ..............................................................................260 16.3.2 Uptake of Dehydroascorbic Acid into Cells .....................................260 16.3.3 Active Transport of Ascorbic Acid ................................................... 261 16.3.4 Cotransporters SVCT1 and SVCT2 .................................................. 262
16.3.4.1 Gene Structure and Expression .......................................... 262 16.3.4.2 Protein Structure ................................................................ 262 16.3.4.3 Regulation of Gene Expression .......................................... 263
16.4 Ascorbic Acid and Gene Expression ............................................................265 16.5 Associated Pathophysiology .........................................................................266
