This second gene, activated whenever the gene for P16INK4A was active, produced a protein that was harmless in itself, but which could be made deadly by the presence of a particular drug.

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Muscles need protein, and many vegetarians, especially those who are physically active, are consuming too little protein.

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An active gene produces a specific protein, but when the body has enough of that protein, the gene releases an inhibitor to stop production.

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C-fos, a protein produced by active nerve cells.

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In January last year he gave a lecture at the UCSD Cancer Center on "in vivo protein transduction, " a means to deliver biologically active molecules, such as therapeutic peptides and proteins, inside the cell.

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These work by binding chemically to that enzyme's active site to inhibit its action. (Protease cuts the raw chain of virus protein produced by a subverted cell into functional molecules.) However, the mechanism is not quite identical.

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