Of the three haptoglobin phenotypes, Hp 1-1 is the most effective in binding free hemoglobin and in suppressing the inflammatory responses associated with free hemoglobin. Hp 1-1 protects against vascular complications in diabetes, is associated with sickle cell anemia, and is more common than other phenotypes in cases of cirrhosis. Individuals who are phenotype 1-1 have the highest concentration of haptoglobin in plasma. MW: 86 kDa. Purity ≥95%