Nn̄g-chheng-chit
Nn̄g-chheng-chit, ia̍h sī kóng nn̄g-pe̍h-chit, tàn-pe̍h-chit, chi̍t khoán ho̍k-cha̍p ê bu̍t-chit, oa̍h-mi̍h sin-khu téng lóng ū, koan-hē tio̍h iàu-kín sèⁿ-miā ê hòa-ha̍k kòe-têng.
Nn̄g-chheng-chit sī chē-chē a-mi-no͘ sng kat chò-hóe pìⁿ tn̂g-liān-á, koh áu chò chi̍t chhok tōa hun-chú. Thian-jiân thang kat chò nn̄g-chheng-chit ê a-mi-no͘ sng ū 20 kúi chióng. Si̍t-bu̍t ū lêng-le̍k ka-tī khip-siu goân-liāu ha̍p-sêng choân-pō͘ só͘ khiàm-ēng ê a-mí-no͘h sng, nā tōng-bu̍t bô-hoat-tō͘, tio̍h tùi thé gōa ê lâi-goân tit-tio̍h iú-ki êng-ióng hun.
Kò͘-sêng
Só͘-ū nn̄g-chheng-chit lóng hâm α a-mi-no͘ sng tn̂g liān-á. α ê ì-sù sī a-mi-no͘ ki (amino group, kì-hō ―NH2) chiap tī pian-hō α ê thòaⁿ-sò͘ goân-chú téng-bīn. Á chit lia̍p thòaⁿ-sò͘ mā kap kha-bó͘-sng ki (carboxyl group, ―COOH) sio-chiap.