The PK₁,pK₂,and PK_R for the Amino Acid Cysteine Are 1 $\alpha$

The pK₁,pK₂,and pK_R for the amino acid cysteine are 1.9,10.7,and 8.4,respectively.At pH 5.0,cysteine would be charged predominantly as follows:

A) " $\alpha$ -carboxylate 0, $\alpha$ -amino 0,sulfhydryl 0,net charge 0"
B) " $\alpha$ -carboxylate +1, $\alpha$ -amino −1,sulfhydryl −1,net charge −1"
C) " $\alpha$ -carboxylate −1, $\alpha$ -amino +1,sulfhydryl +1,net charge +1"
D) " $\alpha$ -carboxylate −1, $\alpha$ -amino +1,sulfhydryl 0,net charge 0"
E) " $\alpha$ -carboxylate +1, $\alpha$ -amino −1,sulfhydryl 0,net charge 0"