The `pK_(a_1), pK_(a_2) and pK_(a_3)` value for the amino acid cysteine `(HS-CH_2-undersetunderset(NH_2)(|)CH-COOH)` are respectively 1.8, 8.3, 10.8. What is isoelectric point of cysteine amino acid ?

Explanation

To find the isoelectric point (pI) of the amino acid cysteine, we will follow these steps:

### Step 1: Identify the relevant pKa values
The pKa values given for cysteine are:
- \( pK_{a1} = 1.8 \)
- \( pK_{a2} = 8.3 \)
- \( pK_{a3} = 10.8 \)

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