Which is an allosteric protein -a) Transferrinb) Ceruloplasminc) Phosphofructokinase d) Haemoglobin

Hemoglobin is an allosteric protein, i.e. binding of an allosteric modulator to hemoglobin alter binding of other substrate or molecule (i.e. O2). Phosphofructokinase I is an allosteric enzyme and is regulated allosterically in glycolysis. All enzymes (except for ribozymes) are proteins. So PFK-I is an allosteric protein.