Characterization of purified heterologous pituitary luteininzing hormones by dinitrophenylation, digestion with carboxypeptidase A and hydrazinolysis.

Abstract

Purified preparations of ovine, human, bovine and porcine pituitary luteinizing hormones have been characterized in terms of their response to dinitrophenylation, digestion with carboxypeptidase A and hydrazinolysis. Dinitrophenylation of ovine, bovine and porcine LH showed serine, threonine and phenylalanine to be the major amino acids detected. Serine was also found in human LH, along with high levels of valine and aspartic acid. Threonine and phenylalanine were relatively lacking in the human LH fractions studied. Carboxypeptidase A digestion released serine, and then leucine, from ovine and bovine luteinizing hormone. Serine and leucine, as well as glycine, were released rapidly from human and porcine LH, although the sequence of release was not as clear cut as with the ovine and bovine hormones. Hydrazinolysis revealed serine as a major residue in each species LH, together with suprisingly large amounts of phenylalanine. The results are interpreted as i*eflecting interesting patterns of similarity an...