HIBCH is a 386 amino acid protein belonging to the enoyl-CoA hydratase/isomerase family. Localizing to the mitochondria, HIBCH is highly expressed in liver and kidney, with lower levels found in heart, muscle and brain. HIBCH hydrolyzes HIBYL-CoA, a saline catabolite, and β-hydroxypropionyl-CoA, an intermediate in the minor pathway involved in the metabolism of proprionate. Existing as two alternatively spliced isoforms, the gene encoding HIBCH maps to human chromosome 2q32.2. Defects to this gene result in HIBCH deficiency (HIBCHD), known alternatively as deficiency of β-hydroxyisobutyryl CoA deacylase or methacrylic aciduria. HIBCHD is characterized by the accumulation of methacrylyl-CoA, a highly reactive compound that undergoes addition reactions with free sulfhydryl groups. Phenotypic symptoms include early deterioration of neurological function, delayed motor skill development and hypotonia.
Function:
Hydrolyzes 3-hydroxyisobutyryl-CoA (HIBYL-CoA), a saline catabolite. Has high activity toward isobutyryl-CoA. Could be an isobutyryl-CoA dehydrogenase that functions in valine catabolism. Also hydrolyzes 3-hydroxypropanoyl-CoA.
Subcellular Location:
Mitochondrion (By similarity).
Tissue Specificity:
Highly expressed in liver and kidney, also detected in heart, muscle and brain (at protein level). Not detected in lung.
DISEASE:
HIBCH deficiency (HIBCHD) [MIM:250620]: The enzyme defect results in accumulation of methacrylyl-CoA, a highly reactive compound, which readily undergoes addition reactions with free sulfhydryl groups. Affected individuals showed delayed development of motor skills, hypotonia, initial poor feeding, and a deterioration in neurological function during first stages of life. Note=The disease is caused by mutations affecting the gene represented in this entry.
Similarity:
Belongs to the enoyl-CoA hydratase/isomerase family.
SWISS:
Q6NVY1
Gene ID:
26275
Database links:
Entrez Gene: 26275 Human
Omim: 610690 Human
SwissProt: Q6NVY1 Human
Unigene: 656685 Human
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