二十种氨基酸是指甘氨酸、丙氨酸、缬氨酸、亮氨酸、异亮氨酸、甲硫氨酸(蛋氨酸)、脯氨酸、色氨酸、丝氨酸、酪氨酸、半胱氨酸、苯丙氨酸、天冬酰胺、谷氨酰胺、苏氨酸、天冬氨酸、谷氨酸、赖氨酸、精氨酸和组氨酸这二十种组成人体蛋白质的氨基酸。
图 3 显示了色氨酸,二十种标准氨基酸中的一种(图像提供了一对立体模型;见 参考资料)。
Figure 3 shows tryptophan, one of the 20 standard amino acids (image is a stereo pair; see Resources for the image source).
蛋白质中出现的氨基酸共有二十种,数百个到数千个单位串连起来。
Twenty different amino acids are common to proteins, linked in chains of hundreds to thousands of units.
There are 64 combinations of three bases and I only need to describe 20, so there's combinations to spare.
三个一组的碱基产生六十四种组合,而我只需对应二十种氨基酸,所以一种氨基酸会对应不同密码子
I'd only have 16 possible two base sequences, that's not enough to specify over 20 amino acids.
如果两个碱基一组那一共只有十六种组合,不够和二十种氨基酸来一一对应
There are more than 20 amino acids that make up the biological polymers called proteins, so there are 20 choices of each amino acid at a position on a protein.
而那些称为蛋白质的生物活性多聚体,是由二十种不同氨基酸所构成,因此每个蛋白质的,任意位点都有多达二十种氨基酸可供选择
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