万物简史 第602期:生命的物质(28)（在线收听）

Proteins, you will remember, are the workhorses of all living systems; as many as a hundred million of them may be busy in any cell at any moment. That's a lot of activity to try to figure out.

你可能记得，蛋白质是所有生命系统的役马：每个细胞中都有多达1亿计的蛋白质在一刻不停地工作。它们的活动如此之多，令人无法捉摸。

Worse, proteins' behavior and functions are based not simply on their chemistry, as with genes, but also on their shapes. To function, a protein must not only have the necessary chemical components, properly assembled, but then must also be folded into an extremely specific shape. "Folding" is the term that's used, but it's a misleading one as it suggests a geometrical tidiness that doesn't in fact apply. Proteins loop and coil and crinkle into shapes that are at once extravagant and complex. They are more like furiously mangled coat hangers than folded towels.

更糟糕的是，蛋白质的行为方式和功能不仅像基因那样取决于它们的化学性质，而且取决于它们的形状。若要具有正常功能，一个蛋白质必须具备以恰当的方式组合在一起的化学成分，之后还必须折叠成一种非常特别的形状。这里所使用的“折叠”这个词实际上是一种容易引起混淆的概念，仿佛是几何学意义上的齐整的意思，其实并不是这样的。蛋白质卷成的和盘折成的形状又随意又复杂，与其说它们像拆叠好的毛巾，倒不如说它们像乱作一团的衣架。

Moreover, proteins are (if I may be permitted to use a handy archaism) the swingers of the biological world. Depending on mood and metabolic circumstance, they will allow themselves to be phosphorylated, glycosylated, acetylated, ubiquitinated, farneysylated, sulfated, and linked to glycophosphatidylinositol anchors, among rather a lot else. Often it takes relatively little to get them going, it appears. Drink a glass of wine, as Scientific American notes, and you materially alter the number and types of proteins at large in your system. This is a pleasant feature for drinkers, but not nearly so helpful for geneticists who are trying to understand what is going on.

除此以外，蛋白质还是生物世界的登徒子（请允许我使用一个信手得来的古词）。根据一时的兴起及新陈代谢的状况，它们会随心所欲地磷硫酸化、糖基化、乙酰化、泛素化、硫酸盐化，以及其他许多种不同的变化。往往，似乎并不需要花费太大力气就会使它们发生变化。饮一杯酒，正如《科学美国人》所说的那样，你就会极大地改变你整个系统内的蛋白质的数量和种类。对于瘾君子来说，这倒是令人高兴的一件事，但是对那些试图搞清楚这一切是怎么发生的遗传学家来说，却根本没有帮助。