12-((5-Iodo-4-azido-2-hydroxybenzoyl)amino)dodecanoic acid: Biological recognition by cholesterol esterase and acyl-CoA:cholesterol O-acyltransferase

Journal Article · Tue Feb 13 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00458a042· OSTI ID:6810578

Kinnunen, P M; Klopf, F H; Bastiani, C A; Gelfman, C M; Lange, L G ^[1]

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1. Jewish Hospital of St. Louis, MO (USA)

Potential probes of protein cholesterol and fatty acid binding sites, namely, 12-((5-iodo-4-azido-2-hydroxybenzoyl)amino)dodecanoate (IFA) and its coenzyme A (IFA:CoA) and cholesteryl (IFA:CEA) esters, were synthesized. These radioactive, photoreactive lipid analogues were recognized as substrates and inhibitors of acyl-CoA;cholesterol O-acyltransferase (ACAT) and cholesterol esterase, neutral lipid binding enzymes which are key elements in the regulation of cellular cholesterol metabolism. In the dark, IFA reversibly inhibited cholesteryl ({sup 14}C)oleate hydrolysis by purified bovine pancreatic cholesterol esterase with an apparent K{sub i} of 150 {mu}M. Cholesterol esterase inhibition by IFA became irreversible after photolysis with UV light and oleic acid provided 50% protection against inactivation. Incubation of homogeneous bovine pancreatic cholesterol esterase with IFA:CEA resulted in its hydrolysis to IFA and cholesterol, indicating recognition of IFA:CEA as a substrate by cholesterol esterase. The coenzyme A ester, IFA:CoA, was a reversible inhibitor of microsomal ACAT activity under dark conditions, and photolysis resulted in irreversible inhibition of enzyme activity with 87% efficiency. IFA:CoA was also recognized as a substrate by both liver and aortic microsomal ACATs, with resultant synthesis of {sup 125}IFA:CEA. IFA and its derivatives, IFA:CEA and IFA:CoA, are thus inhibitors and substrates for cholesterol esterase and ACAT. Biological recognition of these photoaffinity lipid analogues will facilitate the identification and structural analysis of hitherto uncharacterized protein lipid binding sites.

• OSTI ID: 6810578
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:6; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
AORTA
ARTERIES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD VESSELS
BODY
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHOLESTEROL
COENZYMES
DAYS LIVING RADIOISOTOPES
DECANOIC ACID
DECOMPOSITION
DERIVATIZATION
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESTERASES
GLANDS
HALIDES
HALOGEN COMPOUNDS
HALOGENATION
HYDROLASES
HYDROXY COMPOUNDS
INORGANIC PHOSPHORS
INTERMEDIATE MASS NUCLEI
IODIDES
IODINATION
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIVER
METABOLISM
MICROSOMES
MONOCARBOXYLIC ACIDS
NUCLEI
ODD-EVEN NUCLEI
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PANCREAS
PHOSPHORS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PROTEIN STRUCTURE
RADIOISOTOPES
REACTION KINETICS
RIBOSOMES
SODIUM COMPOUNDS
SODIUM IODIDES
STEROIDS
STEROLS
TRANSFERASES