What question did this study set out to answer?

To characterize soluble hepatic δ-aminolevulinic acid synthetase, elucidate its catalytic pathway, and assess end-product inhibition by hemin and related tetrapyrroles.

July 1, 1972Journal of Biological ChemistryOpen Access

Soluble δ-Aminolevulinic Acid Synthetase of Rat Liver

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Authors

PSPerry L. ScholnickUniversity of California, Los Angeles LHLydia HammakerUniversity of California, San Francisco HMHarvey S. MarverUniversity of California, San Francisco

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Implication

Biochemical analysis reveals the catalytic mechanism and feedback inhibition of soluble delta-aminolevulinic acid synthetase in rat liver, highlighting regulatory controls in heme synthesis.

Key Points

To characterize soluble hepatic δ-aminolevulinic acid synthetase, elucidate its catalytic pathway, and assess end-product inhibition by hemin and related tetrapyrroles.
Isolated soluble δ-aminolevulinic acid synthetase from rat liver tissue.
Conducted isotopic reaction profiling using [1-14C]glycine and specific inhibitors to determine the sequential reaction mechanism.
Assessed enzyme inhibition kinetics using hemin, bilirubin, and various porphyrins and metalloporphyrins.
Identified an active-center sulfhydryl group essential for initial cofactor pyridoxal-5'-phosphate binding through a thiohemiacetal intermediate.
Demonstrated end-product feedback inhibition by hemin with an inhibition constant (Ki) of 2 x 10^-5 M.
Showed that metalloporphyrins, porphyrins, and bilirubin inhibit enzyme activity with relative potencies dependent on tetrapyrrole net charge.

Cite This Study

Scholnick et al. (1972) studied this question.

synapsesocial.com/papers/6a8bf044eada60f85de3d0b4 https://doi.org/10.1016/s0021-9258(19)45050-3

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Implication

Biochemical analysis reveals the catalytic mechanism and feedback inhibition of soluble delta-aminolevulinic acid synthetase in rat liver, highlighting regulatory controls in heme synthesis.

Soluble δ-Aminolevulinic Acid Synthetase of Rat Liver

Discussion

Member takes

Implication

Key Points

Cite This Study

Soluble δ-Aminolevulinic Acid Synthetase of Rat Liver

Discussion

Member takes

Implication

Key Points

Cite This Study

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