In Vitro Inhibition of Chick Embryo Lysyl Hydroxylase by Homogentisic Acid: A PROPOSED CONNECTIVE TISSUE DEFECT IN ALKAPTONURIA
AUTOR(ES)
Murray, John C.
RESUMO
Homogentisic acid inhibits the in vitro activity of chick embryo lysyl hydroxylase, a microsomal enzyme which catalyzes the transformation of certain lysyl residues in collagen to hydroxylysine. Chick embryo lysyl hydroxylase activity was measured as specific tritium release as tritium water from a [4,5-3H]lysine-labeled unhydroxylated collagen substrate prepared from chick calvaria. Kinetic studies revealed a linear, noncompetitive type of inhibition with respect to collagen substrate with a Ki of 120-180 μM. The inhibition by homogentisic acid was reversible in that enzyme activity could be restored after dialysis of preincubated mixtures of homogentisic acid with enzyme or substrate. The inhibition by homogentisic acid was competitive with respect to ascorbic acid, and the addition of reducing agents, such as ascorbic acid or 1,4-dithiothreitol, protected lysyl hydroxylase activity from homogentisic acid inhibition.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372319Documentos Relacionados
- Observations on connective tissue tensile strength in the chick embryo.
- Abnormal copper metabolism and deficient lysyl oxidase activity in a heritable connective tissue disorder.
- Quantitative Aspects of Inhibition of Virus Replication by Interferon in Chick Embryo Cell Cultures
- Myotonic dystrophy: investigation of the proposed defect in guanidoacetic acid synthesis
- THE INDUCTION OF δ-AMINOLEVULINIC ACID SYNTHETASE in vivo IN CHICK EMBRYO LIVER BY NATURAL STEROIDS*