Display Settings:

Format

Send to:

Choose Destination
Brain Res. 1991 Mar 1;542(2):307-12.

Two kynurenine aminotransferases in human brain.

Author information

  • 1Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, 21228.

Abstract

Using Tris-acetate buffer rather than conventional phosphate buffer, it was possible to detect two distinct proteins capable of producing the neuroinhibitory brain metabolite kynurenic acid (KYNA) from L-kynurenine in human brain tissue. The two kynurenine aminotransferases (KATs), arbitrarily termed 'KAT I' and 'KAT II', could be physically separated by isoelectric focussing on a pH 3-10 Ampholine gradient, and, more completely, by differential elution from a DEAE-Sepharose column. KAT I showed a pronounced preference for pyruvate as a co-factor and had a pH optimum of 9.6. In contrast, KAT II was virtually equally active when either pyruvate or 2-oxoglutarate were used as the aminoacceptor, and its pH optimum was 7.4. Moreover, KAT I and KAT II differed with regard to their sensitivity to amino acids and as the aminoacceptor, and its pH optimum was 7.4. Moreover, KAT I and KAT II differed with regard to their sensitivity to amino acids and kinetic characteristics. The existence of two separate enzymes capable of producing KYNA in the human brain raises the question if and to what extent each of the enzymes regulates the cerebral synthesis of KYNA and its possible role as a modulator of excitatory amino acid receptor function.

PMID:
2029638
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk