{"doi":"10.1042/bj1370015","title":"An enzyme-bound intermediate in the biosynthesis of 3-hydroxy-3-methylglutaryl-coenzyme A","abstract":"<jats:p>1. Purified 3-hydroxy-3-methylglutaryl-CoA synthase from baker's yeast (free from acetoacetyl-CoA thiolase activity) catalysed an exchange of acetyl moiety between 3′-dephospho-CoA and CoA. The exchange rate was comparable with the overall velocity of synthesis of 3-hydroxy-3-methylglutaryl-CoA. 2. Acetyl-CoA reacted with the synthase, giving a rapid ‘burst’ release of CoA proportional in amount to the quantity of enzyme present. The ‘burst’ of CoA was released from acetyl-CoA, propionyl-CoA and succinyl-CoA (3-carboxypropionyl-CoA) but not from acetoacetyl-CoA, hexanoyl-CoA, dl-3-hydroxy-3-methylglutaryl-CoA, or other derivatives of glutaryl-CoA. 3. Incubation of 3-hydroxy-3-methylglutaryl-CoA synthase with [1-14C]acetyl-CoA yielded protein-bound acetyl groups. The Keq. for the acetylation was 1.2 at pH7.0 and 4°C. Acetyl-labelled synthase was isolated free from [1-14C]acetyl-CoA by rapid gel filtration at pH6.1. The [1-14C]acetyl group was removed from the protein by treatment with hydroxylamine, CoA or acetoacetyl-CoA but not by acid. When CoA or acetoacetyl-CoA was present the radioactive product was [1-14C]acetyl-CoA or 3-hydroxy-3-methyl-[14C]glutaryl-CoA respectively. 4. The isolated [1-14C]acetyl-enzyme was slowly hydrolysed at pH6.1 and 4°C with a first-order rate constant of 0.005min-1. This rate could be stimulated either by raising the pH to 7.0 or by the addition of desulpho-CoA. 5. These properties are interpreted in terms of a mechanism in which 3-hydroxy-3-methyl-glutaryl-CoA synthase is acetylated by acetyl-CoA to give a stable acetyl-enzyme, which then condenses with acetoacetyl-CoA yielding a covalent derivative between 3-hydroxy-3-methylglutaryl-CoA and the enzyme which is then rapidly hydrolysed to free enzyme and product.</jats:p>","journal":"Biochemical Journal","year":1974,"id":15448,"datarank":2.572713237126978,"base_score":2.8903717578961645,"endowment":2.8903717578961645,"self_citation_contribution":0.4335557636844247,"citation_network_contribution":2.139157473442553,"self_endowment_contribution":0.4335557636844247,"citer_contribution":2.139157473442553,"corpus_percentile":null,"corpus_rank":null,"citation_count":17,"citer_count":15,"citers_with_citation_signal":14,"citers_with_endowment":14,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":117818,"name":"P. K. Tubbs","orcid":null,"position":1,"is_corresponding":false},{"id":117817,"name":"B. Middleton","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":2.8903717578961645,"endowment":2.8903717578961645,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"4595282","pmcid":"PMC1166075","openalex_id":"https://openalex.org/W2341132672","authors":[],"funders":[],"total_grants":0,"fwci":1.3173,"citation_percentile":0.79201174,"influential_citations":0,"citation_trend":[],"oa_status":"bronze","license":null,"oa_locations":[{"url":"https://portlandpress.com/biochemj/article-pdf/137/1/15/561469/bj1370015.pdf","host_type":"journal"},{"url":"https://europepmc.org/articles/pmc1166075?pdf=render","host_type":"GREEN"},{"url":"https://portlandpress.com/biochemj/article-pdf/137/1/15/561469/bj1370015.pdf","host_type":"publisher"},{"url":"http://portlandpress.com/biochemj/article-pdf/137/1/15/561469/bj1370015.pdf","host_type":"publisher"},{"url":"https://doi.org/10.1042/bj1370015","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/4595282","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/1166075","host_type":"repository"}],"fields_of_study":["Microbial Metabolic Engineering and Bioproduction","Biochemical and Molecular Research","Enzyme Structure and Function","Chemistry","Medicine","Acetyl Coenzyme A","Acyl Coenzyme A","Binding Sites","Carbon Radioisotopes","Chromatography, DEAE-Cellulose","Chromatography, Paper","Coenzyme A","Drug Stability","Glutarates","Hydrogen-Ion Concentration","Kinetics","Oxo-Acid-Lyases","Protein Binding","Saccharomyces cerevisiae","Spectrometry, Fluorescence","Spectrophotometry, Ultraviolet","Structure-Activity Relationship","Time Factors"],"mesh_terms":["Acetyl Coenzyme A","Acyl Coenzyme A","Binding Sites","Carbon Radioisotopes","Chromatography, DEAE-Cellulose","Chromatography, Paper","Coenzyme A","Drug Stability","Glutarates","Hydrogen-Ion Concentration","Oxo-Acid-Lyases","Kinetics","Protein Binding","Saccharomyces cerevisiae","Spectrometry, Fluorescence","Spectrophotometry, Ultraviolet","Structure-Activity Relationship","Time Factors"],"keywords":["Acetyl-CoA","Coenzyme A","Thiolase","ATP synthase","Hydroxylamine","Chemistry","Enzyme","Biosynthesis","Biochemistry","Acetylation","Hydrolysis","Stereochemistry"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-01T17:46:07.133099Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}