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The study of processes within the body. Derived from the Latin physiologia - natural science.
Metabolites of phenylalanine in the urine due to a defective liver enzyme which would normally convert dietary phenylalanine into tyrosine. This is due to a genetic fault. If untreated, PKU can result in severe damage to the developing brain as a result of the toxic build-up of phenylalanine. A routine test is available that can identify the presence of PKU in a baby soon after birth. A special diet low in phenylalanine is required lifelong to enable normal development and the maintenance of normal health in later years. The diet becomes especially critical in mothers-to-be with PKU if their babies are to be protected from damaging levels of phenylalanine.
Molecules characteristic of living systems. They are large, complex molecules built from amino acids. The amino acids are joined to form linear chains, rather like popper beads forming a necklace. The chain of amino acids then folds to form helices and sheets which give the protein molecules their individual shapes. The biological activity of a protein is largely determined by its 3-dimensional shape. Proteins have a number of important functions: as enzymes controlling chemical activities in cells, providing structure to the cell, receiving chemical signals, and in the immune system (eg: antibodies) - to give just a few examples.
The complete set of proteins produced by the genome during the lifetime of the organism. The Human Proteome Organisation (HUPO) looks set to become the successor to the Human Genome Project (HUGO).
The large-scale study of proteins (and their interactions) from cells and organisms. This is linked with the continuing emergence of vast quantities of sequence data from genome studies. For a review of proteomics, see: Pandey, A., and Mann, M. (2000) Proteomics to study genes and genomes. Nature, 405, 837-846 (Jun 15).