Negatively Charged (Acidic) Amino Acids Aspartate: Strong negative charge at pH 7; forms oxaloacetate by transamination; important for albumin’s binding properties. Glutamate: Strong negative charge at pH 7; forms α-ketoglutarate by transamination; important for albumin’s binding properties.Albumin has these Negatively Charged acidic amino acids, which explains why it is a strong binding protein for calcium and other positively charged elements.