Characterization of rat placental lactogen-alpha (PL-alpha) with an antipeptide antibody directed against rat PLs.
We have already reported that the serum of the mid-pregnant rat contains placental lactogen-alpha (PL-alpha), which has a higher molecular weight than PL-I when analysed by gel-filtration chromatography. In order to characterize PL-alpha, we prepared antipeptide antisera directed against the hydrophilic regions of authentic PLs and developed RIAs with them. With these RIAs, antiserum AI-86 reacted only with PL-I, whereas antiserum AII-86 reacted with both PL-alpha and PL-I, which indicates that the antibody recognition sites of these molecules are not identical and their core proteins differ distinctly. As the use of the RIAs with AI-86 and AII-86 in combination enabled PL-alpha and PL-I to be discriminated, the glycoresidues and hydrophobicity of PL-alpha were analyzed further. Analysis with hydrophobic chromatography revealed that PL-alpha was less hydrophobic than PL-I and, furthermore, PL-alpha, but not PL-I, bound specifically to a wheat germ agglutinin (WGA) lectin column. Therefore, in view of their different amino acid sequences and glycoresidues, PL-alpha and PL-I are distinct molecular entities.
Laboratory of Cellular Biochemistry, University of Tokyo, Japan.
N
N
Hattori
M
M
Wakimasu
M
M
Takahashi
M
M
Hirosawa
K
K
Shiota
T
T
Ogawa
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006031:Glycosylation; D007106:Immune Sera; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology*; D010928:Placental Lactogen / Q000737:chemistry; D011247:Pregnancy; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014909:Wheat Germ Agglutinins
D000906:Antibodies; D007106:Immune Sera; D010446:Peptide Fragments; D014909:Wheat Germ Agglutinins; C062303:placental lactogen II; C085699:placental lactogen I, rat; D010928:Placental Lactogen