万物简史 第602期:生命的物质(28)

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 genes¹, but also on their shapes. To function, a protein must not only have the necessary chemical components², 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 extravagant³ and complex. They are more like furiously mangled⁴ coat hangers⁵ 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 metabolic⁶ 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 relatively⁷ 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。

1 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

2 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

3 extravagant   

adj.奢侈的；过分的；(言行等)放肆的

参考例句：

• They tried to please him with fulsome compliments and extravagant gifts.他们想用溢美之词和奢华的礼品来取悦他。
• He is extravagant in behaviour.他行为放肆。

4 mangled   

vt.乱砍（mangle的过去式与过去分词形式）

参考例句：

• His hand was mangled in the machine. 他的手卷到机器里轧烂了。
• He was off work because he'd mangled his hand in a machine. 他没上班，因为他的手给机器严重压伤了。 来自《简明英汉词典》

5 hangers   

n.衣架( hanger的名词复数 )；挂耳

参考例句：

• The singer was surrounded by the usual crowd of lackeys and hangers on. 那个歌手让那帮总是溜须拍马、前呼後拥的人给围住了。 来自《简明英汉词典》
• I want to put some of my good hangers in Grandpa's closet. 我想在爷爷的衣橱放几个好的衣架。 来自辞典例句

6 metabolic   

adj.新陈代谢的

参考例句：

• Impressive metabolic alternations have been undergone during embryogenesis.在胚胎发生期间经历了深刻的代谢变化。
• A number of intoxicants are associated with metabolic acidosis.许多毒性物质可引起代谢性酸中毒。

7 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。