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.
Department of Internal Medicine, School of Medicine, University of California, Davis, California 95616, USA. chhalsted@ucdavis.edu
C H
CH
Halsted
E H
EH
Ling
R
R
Luthi-Carter
J A
JA
Villanueva
J M
JM
Gardner
J T
JT
Coyle
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