What question did this study set out to answer?

To purify soluble δ-aminolevulinic acid synthetase from rat liver cytosol and characterize its stability, molecular weight, and kinetic properties.

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

Experimental study reveals the purification and kinetic properties of cytosolic delta-aminolevulinic acid synthetase in rat liver, highlighting key regulatory mechanisms of heme biosynthesis.

Key Points

To purify soluble δ-aminolevulinic acid synthetase from rat liver cytosol and characterize its stability, molecular weight, and kinetic properties.
Induced the enzyme in rat liver using 2-allyl-2-isopropylacetamide.
Purified the cytosolic enzyme 150- to 200-fold using Sephadex G-50, protamine sulfate and ammonium sulfate fractionation, calcium phosphate gel adsorption, Sephadex G-200 gel filtration, and sucrose density gradient centrifugation.
The enzyme required high cation concentration (0.3 M NaCl) for maximal activation and stability, demonstrating a molecular weight of approximately 300,000 with NaCl versus exceeding 500,000 without NaCl.
Optimal activity occurred at pH 7.5 with an absolute requirement for glycine (Km = 1 x 10^-2 M), succinyl-CoA (Km = 7 x 10^-5 M), and pyridoxal 5'-phosphate (Km = 3 x 10^-6 M).
Substrate specificity was strict: alanine or serine yielded no detectable activity, and substituting propionyl-CoA or acetyl-CoA for succinyl-CoA reduced aminoketone formation to less than 1% of the normal rate.

Cite This Study

Scholnick et al. (1972) studied this question.

synapsesocial.com/papers/6a8bf044eada60f85de3d0b3 https://doi.org/10.1016/s0021-9258(19)45049-7

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Implication

Experimental study reveals the purification and kinetic properties of cytosolic delta-aminolevulinic acid synthetase in rat liver, highlighting key regulatory mechanisms of heme biosynthesis.

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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