Fetal liver alanine: Glyoxylate aminotransferase and the prenatal diagnosis of primary hyperoxaluria type 1

1989 ◽  
Vol 9 (4) ◽  
pp. 271-281 ◽  
Author(s):  
Christopher J. Danpure ◽  
Patricia R. Jennings ◽  
Richard J. Penketh ◽  
Pauline J. Wise ◽  
Penelope J. Cooper ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Fetal Liver ◽  
Primary Hyperoxaluria ◽  
Primary Hyperoxaluria Type 1 ◽  
Primary Hyperoxaluria Type ◽  
Glyoxylate Aminotransferase ◽  
Hyperoxaluria Type

scholarly journals A Semiautomated Alanine: Glyoxylate Aminotransferase Assay for the Tissue Diagnosis of Primary Hyperoxaluria Type 1

1997 ◽  
Vol 34 (4) ◽  
pp. 400-404 ◽  
Author(s):  
G Rumsby ◽  
T Weir ◽  
C T Samuell
Keyword(s):  
Enzyme Activity ◽  
Fetal Liver ◽  
Primary Hyperoxaluria ◽  
Sensitive Assay ◽  
Primary Hyperoxaluria Type 1 ◽  
Primary Hyperoxaluria Type ◽  
Alanine:Glyoxylate Aminotransferase ◽  
Glyoxylate Aminotransferase ◽  
Hyperoxaluria Type

We have developed a sensitive assay for the measurement of alanine:glyoxylate aminotransferase (EC 2.6.1.44) activity in human liver. The assay is partly automated, and takes into consideration the sensitivity of the reaction to pH and to glyoxylate concentration. It is less subject to interference from other enzymes utilizing glyoxylate and to chemical interference from glyoxylate itself and can therefore be used without correction for cross-over by glutamate:glyoxylate aminotransferase (EC 2.6.1.4). The assay allows clear discrimination between normal and affected livers and is sufficiently sensitive to measure enzyme activity in fetal liver samples. Enzyme activity ranged from 17·9 to 38·5 μmol/h/mg protein in control livers ( n = 9) and 0·8 to 9·5 μmol/h/mg protein in 30 of 39 hyperoxaluric patients studied. Normal alanine: glyoxylate aminotransferase activity (from 22·8 to 45·5 μmol/h/mg protein) allowed exclusion of primary hyperoxaluria type 1 in the other nine hyperoxaluric patients.

scholarly journals Identification of mutations associated with peroxisome-to-mitochondrion mistargeting of alanine/glyoxylate aminotransferase in primary hyperoxaluria type 1.

1990 ◽  
Vol 111 (6) ◽  
pp. 2341-2351 ◽  
Author(s):  
P E Purdue ◽  
Y Takada ◽  
C J Danpure
Keyword(s):  
Normal Population ◽  
Primary Hyperoxaluria ◽  
Alpha Helix ◽  
Primary Hyperoxaluria Type 1 ◽  
Peroxisomal Enzyme ◽  
Primary Hyperoxaluria Type ◽  
Oligonucleotide Hybridization ◽  
Glyoxylate Aminotransferase ◽  
Hyperoxaluria Type

We have previously shown that in some patients with primary hyperoxaluria type 1 (PH1), disease is associated with mistargeting of the normally peroxisomal enzyme alanine/glyoxylate aminotransferase (AGT) to mitochondria (Danpure, C.J., P.J. Cooper, P.J. Wise, and P.R. Jennings. J. Cell Biol. 108:1345-1352). We have synthesized, amplified, cloned, and sequenced AGT cDNA from a PH1 patient with mitochondrial AGT (mAGT). This identified three point mutations that cause amino acid substitutions in the predicted AGT protein sequence. Using PCR and allele-specific oligonucleotide hybridization, a range of PH1 patients and controls were screened for these mutations. This revealed that all eight PH1 patients with mAGT carried at least one allele with the same three mutations. Two were homozygous for this allele and six were heterozygous. In at least three of the heterozygotes, it appeared that only the mutant allele was expressed. All three mutations were absent from PH1 patients lacking mAGT. One mutation encoding a Gly----Arg substitution at residue 170 was not found in any of the control individuals. However, the other two mutations, encoding Pro----Leu and Ile----Met substitutions at residues 11 and 340, respectively, cosegregated in the normal population at an allelic frequency of 5-10%. In an individual homozygous for this allele (substitutions at residues 11 and 340) only a small proportion of AGT appeared to be rerouted to mitochondria. It is suggested that the substitution at residue 11 generates an amphiphilic alpha-helix with characteristics similar to recognized mitochondrial targeting sequences, the full functional expression of which is dependent upon coexpression of the substitution at residue 170, which may induce defective peroxisomal import.

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