Folylpoly-gamma-glutamate carboxypeptidase from pig jejunum. Molecular characterization and relation to glutamate carboxypeptidase II.
Jejunal folylpoly-gamma-glutamate carboxypeptidase hydrolyzes dietary folates prior to their intestinal absorption. The complete folylpoly-gamma-glutamate carboxypeptidase cDNA was isolated from a pig jejunal cDNA library using an amplified homologous probe incorporating primer sequences from prostate-specific membrane antigen, a protein capable of folate hydrolysis. The cDNA encodes a 751-amino acid polypeptide homologous to prostate-specific membrane antigen and rat brain N-acetylated alpha-linked acidic dipeptidase. PC3 transfectant membranes exhibited activities of folylpoly-gamma-carboxypeptidase and N-acetylated alpha-linked acidic dipeptidase, while immunoblots using monoclonal antibody to native folylpoly-gamma-glutamate carboxypeptidase identified a glycoprotein at 120 kDa and a polypeptide at 84 kDa. The kinetics of native folylpoly-gamma-carboxypeptidase were expressed in membranes of PC3 cells transfected with either pig folylpoly-gamma-carboxypeptidase or human prostate-specific membrane antigen. Folylpoly-gamma-carboxypeptidase transcripts were identified at 2.8 kilobase pairs in human and pig jejunum, human and rat brain, and human prostate cancer LNCaP cells. Thus, pig folylpoly-gamma-carboxypeptidase, rat N-acetylated alpha-linked acidic dipeptidase, and human prostate-specific membrane antigen appear to represent varied expressions of the same gene in different species and tissues. The discovery of the jejunal folylpoly-gamma-carboxypeptidase gene provides a framework for future studies on relationships among these proteins and on the molecular regulation of intestinal folate absorption.
Halsted
C H
CH
Department of Internal Medicine, School of Medicine, University of California, Davis, California 95616, USA. chhalsted@ucdavis.edu
Ling
E H
EH
Luthi-Carter
R
R
Villanueva
J A
JA
Gardner
J M
JM
Coyle
J T
JT
D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface; D001483:Base Sequence; D002268:Carboxypeptidases / Q000737:chemistry; D003001:Cloning, Molecular; D005492:Folic Acid / Q000378:metabolism; D043425:Glutamate Carboxypeptidase II; D006023:Glycoproteins / Q000737:chemistry; D006801:Humans; D007583:Jejunum / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D017430:Prostate-Specific Antigen / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014162:Transfection / Q000235:genetics; D011623:gamma-Glutamyl Hydrolase / Q000737:chemistry*
D000954:Antigens, Surface; D006023:Glycoproteins; D012333:RNA, Messenger; D005492:Folic Acid; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D011623:gamma-Glutamyl Hydrolase; D017430:Prostate-Specific Antigen