Arginine racemase from Pseudomonas graveolens is inactivated by preliminary incubation with Lor D-ornithine, 6-Nacetyl-L-ornithine, and L-2,4-diaminobutyrate at pH 10.0. Loss of the enzyme activity is associated with formation of a new spectrum with an absorption maximum in the region of 320 rnp and disappearance of a peak at 420 mp. The inactivation is prevented, and the inactivated enzyme is ...

A full-term female neonate developed focal motor seizures at 1 hour of life, followed by paroxysmal nonepileptic abnormal eye–head movements on day 5 (video 1). CSF revealed mild hypoglycorrhachia, borderline low CSF:serum glucose, and pyridoxal-5′-phosphate (P5P). Genetic testing showed compound heterozygous mutations in the pyridoxamine 5′-phosphate oxidase ( PNPO ) gene consistent with P5P-d...

Aspartate and glutamate react instantaneously with the pyridoxal form of the pig heart glutamic aspartic transaminase (1) to yield the corresponding keto acid, converting the enzymebound pyridoxal phosphate to bound pyridoxamine phosphate (2). Other amino acids such as methionine sulfoxide, methionine sulfone, and alanine react much more slowly with the enzyme, but the reaction itself appears t...

The reaction catalyzed by purified rat liver cytosol tyrosine aminotransferase (L-tyrosine + 2 oxoglutarate = p-hydroxyphenylpyruvate + L-glutamate, EC 2.6.1.5) has been analyzed with regard to product inhibition and combination with each of its rate-limiting substrates by the Hill equation. Glutamate is a linear competitive inhibitor with respect to tyrosine, a linear noncompetitive inhibitor ...