I need help w/ a question: Insulin protein has 2 polypeptides A and B. Human and duck insulins have the same sequence except for six below. Is the pI of human insulin higher or lower than duck insulin?

AA seq. A8 A9 A10 B1 B2 B27
Human Thr Ser Ile Phe Val Thr
Duck Glu Asn Pro Ala Ala Ser