Permohonan diterimi

Permohonan diterimi

結果 (中文) 1:

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結果 (中文) 2:

Charged Polar Side Chains Are Positively or Negatively Charged. Five amino acids have charged side chains (Table 4-1 and Fig. 4-7). The side chains of the basic amino acids are positively charged at physiological pH values. Lysine has a butylammonium side chain, and arginine bears a guanidino group. As shown in Table 4-1, histidine carries an imidazolium moiety. Note that only histidine, with a pKR of 6.04, readily ionizes within the physiological pH range. Consequently, both the neutral and cationic forms occur in proteins. In fact, the protonation–deprotonation of histidine side chains is a feature of numerous enzymatic reaction mechanisms.
The side chains of the acidic amino acids, aspartic acid and glutamic acid, are negatively charged above pH 3; in their ionized state, they are often referred to as aspartate and glutamate. Asparagine and glutamine are, respectively, the amides of aspartic acid and glutamic acid.