Phosphorylation of delta sleep-inducing peptide (DSIP) by casein kinase II in vitro.
Nakamura. A A; Shiomi. H H
Key Findings
- DSIP is a substrate for casein kinase II in vitro
- Apparent Km = 20 mM and Vmax = 90.9 nmol/min/mg protein for the phosphorylation reaction
- Both ATP and GTP can serve as phosphate donors; heparin inhibits, spermine enhances the reaction
Practical Outcomes
- For most DIY health enthusiasts, this study doesn’t change how you would take DSIP, because it only describes a lab‑based chemical reaction and offers no data on effects in humans. It suggests that DSIP’s activity might be altered by phosphorylation, but without in‑vivo evidence there’s no actionable protocol to adjust dosage or combine it with other supplements.
Summary
Scientists showed that the peptide DSIP can be chemically modified (phosphorylated) by an enzyme called casein kinase II in a test‑tube experiment. They measured how efficiently this happens and found that both ATP and GTP can donate the phosphate, while certain chemicals can block or boost the reaction.
Abstract
A phosphorylated analogue of DSIP at Ser7 has been shown to exist endogenously by immunochemical studies. An enzyme which could phosphorylate DSIP has not yet been identified. In the present study, we examined DSIP as a substrate for in vitro phosphorylation by casein kinase II. DSIP was phosphorylated by the enzyme with apparent Km and Vmax values of 20 mM and 90.9 nmol/min/mg protein, respectively. Both ATP and GTP were utilized as phosphoryl donors. Phosphorylation of DSIP was inhibited by heparin and enhanced by spermine. These results demonstrate that DSIP can serve as a possible substrate for casein kinase II in vitro.
Study Information
pubmed
1991
10.1016/0196-9781(91)90222-b