Characterization and primary sequence of a human hepatic microsomal estriol UDPglucuronosyltransferase.
A human liver microsomal UDP glucuronosyltransferase (UDPGT) that demonstrates reactivity with estriol (pI 7.4 UDPGT) has been purified to homogeneity and characterized further. No activity toward morphine, 4-hydroxybiphenyl, bilirubin, or tripelennamine was observed. The estriol UDPGT shows immunoreactivity with antibodies raised against rat hepatic microsomal 3 alpha- and 17 beta-hydroxysteroid UDPGTs but not with antibodies raised against rat hepatic microsomal p-nitrophenol UDPGT. The NH2-terminal sequence of the purified protein was determined and found to correspond to an identical sequence in the deduced amino acid sequence of a cDNA obtained from a human liver library in lambda gt11 (HLUG4). Sequence analysis revealed that HLUG4 is 2094 bp in length and encodes a protein of 523 amino acids which has a 16 amino acid leader sequence, followed by an untranslated 3' region of 525 bp. Three potential N-glycosylation sites were identified in the predicted sequence. The deduced amino acid sequence of estriol UDPGT showed 82% identity with the deduced amino acid sequence of another human hepatic cDNA (HLUG25), which has been expressed as a UDPGT capable of 6 alpha-hydroxyglucuronidation of hyodeoxycholic acid, strongly suggesting that these proteins are members of the same gene subfamily.
Coffman
B L
BL
Department of Pharmacology, University of Iowa, Iowa City 52242.
Tephly
T R
TR
Irshaid
Y M
YM
Green
M D
MD
Smith
C
C
Jackson
M R
MR
Wooster
R
R
Burchell
B
B
D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000032:analysis*; D004964:Estriol / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification*; D008862:Microsomes, Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D013379:Substrate Specificity
D007527:Isoenzymes; D004247:DNA; D014453:Glucuronosyltransferase; D004964:Estriol