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B6db references: 95096006

type Journal Article
authors Lee, I. S.; Takio, K.; Kido, R.; Titani, K.
title Purification and amino- and carboxyl-terminal amino acid sequences of alanine-glyoxylate transaminase 1 from human liver
journal J Biochem (Tokyo)
ui 95096006
year (1994)
volume 116
number 1
pages 12-7.
keywords Alanine Transaminase/*chemistry/isolation & purification
abstract In order to confirm the amino acid sequence predicted from the nucleotide sequence of cDNA and also to elucidate the intracellular localization and molecular evolution, human liver alanine-glyoxylate transaminase 1 (AGT1) was purified and subjected to partial amino acid sequence determination, with special attention to posttranslational modification. The enzyme was purified to homogeneity from the 10,000 x g supernatant of human liver homogenate. The purified enzyme showed only a single protein band at about 43 kDa on SDS-PAGE, indicating that it is a homodimer of two identical subunits, because the native enzyme has a molecular mass of about 80 kDa. Both the amino- and carboxyl- terminal peptides of the enzyme were isolated from a cyanogen bromide digest of the S-carboxyl-methylated protein and subjected to amino acid sequence determination. The alpha-amino group of the amino-terminal peptide was shown to be blocked by an acetyl group. The carboxyl- terminal sequence contained a putative N-glycosylation sequence (-Asn- Ala-Thr-), the only one present in the whole molecule, but this sequence was normally determined, indicating that the enzyme is not N- glycosylated. Purdue et al. [J. Cell Biol. 111, 2341-2351 (1990)] have reported that Pro-11, Gly-170, and Ile-340 in normal human AGT1 were replaced by Leu, Arg, and Met, respectively, in a patient with primary hyperoxaluria type 1. We confirmed that residue-11 was Pro. Both the amino- and carboxyl-terminal sequences of the enzyme showed extensive similarity with those of rat liver mitochondrial serine-pyruvate aminotransferase and the small chain of hydrogenase from a thermophilic unicellular cyanobacterium, Synechococcus PCC 6716.(ABSTRACT TRUNCATED AT 250 WORDS)
last changed 2002/11/12 16:17

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