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Human phosphoserine 31 corticotropin1-39. Isolation and characterization
The Journal of Biological Chemistry
|July 10, 1983
Summary
Researchers discovered two forms of human corticotropin (ACTH), one phosphorylated at serine 31. Both forms demonstrated equal potency in stimulating steroid production, suggesting phosphorylation does not alter ACTH
Area of Science:
- Endocrinology
- Biochemistry
Background:
- Corticotropin (ACTH) is a crucial hormone regulating adrenal steroidogenesis.
- Human ACTH exists in various forms, but their functional differences are not fully understood.
Purpose of the Study:
- To isolate and characterize distinct forms of human ACTH.
- To investigate the functional significance of ACTH phosphorylation in steroidogenesis.
Main Methods:
- Reversed-phase chromatography for ACTH isolation and purification.
- Structural analysis to identify post-translational modifications.
- In vitro bioassays using rat and human adrenal cells to assess steroidogenic potency.
Main Results:
- Two forms of human ACTH1-39 were isolated: a nonphosphorylated form and a form phosphorylated at serine 31.
- Approximately 30% of ACTH in both adult and fetal pituitaries was phosphorylated.
- Both phosphorylated and nonphosphorylated ACTH were equipotent in stimulating steroid production in adrenal cell bioassays.
Conclusions:
- Human ACTH1-39 exists in phosphorylated and nonphosphorylated forms.
- Phosphorylation at serine 31 does not affect the steroidogenic activity of ACTH.
- The functional role of ACTH phosphorylation warrants further investigation.