Skip to content

Study · Not a test of the peptide alone · 1990

4 results

Fragmentation of isoaspartyl peptides and proteins by carboxypeptidase Y: release of isoaspartyl dipeptides as a result of internal and external cleavage.

Johnson BA, Aswad DW

Biochemistry1 May 1990Cited by 36 (Europe PMC)

PMID2140948 (opens in a new tab)DOI10.1021/bi00470a017 (opens in a new tab)PepBankPUB-02140948
Publisher pagePubMedAsk about this study
Jump to 4 results

Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study4

No result from this study comes from a test of the peptide.

Studies that did not test the peptide alone4

In this study, Delta sleep-inducing peptide (DSIP) was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking Delta sleep-inducing peptide (DSIP).

  1. 01LabNot a test of Delta sleep-inducing peptide (DSIP) aloneIn vitro (cell-free)Other

    In vitro, carboxypeptidase Y cleaved isoaspartate-containing DSIP at an internal site, between the isoaspartate and the preceding amino acid.

    In plain wordsIn lab tests, an enzyme cut a modified form of DSIP at an inside position.

    Peptide
    Delta sleep-inducing peptide (DSIP)
    Outcome
    Not applicableInternal cleavage of isoaspartyl DSIP by carboxypeptidase Y
    Study

    n: not reported in source

    In vitro digestion by carboxypeptidase Y
    Outcome group
    Analytical methods and detection · Pharmacology

    Source sentences

    Summary
    Isoaspartate-containing versions of sea urchin sperm-activating peptide, delta sleep-inducing peptide, and lactate dehydrogenase (231-242) were cleaved at internal sites by carboxypeptidase Y. Cleavage occurred between the isoaspartate and the preceding amino acid, and it was accompanied by sequenti…

    In this study, Delta sleep-inducing peptide (DSIP) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Delta sleep-inducing peptide (DSIP).

  2. 02LabNot a test of Delta sleep-inducing peptide (DSIP) aloneIn vitro (cell-free)Other

    In vitro, isoaspartyl bonds in the peptides were not cleaved by carboxypeptidase Y, so isoaspartyl dipeptides were among the final products.

    In plain wordsIn lab tests, the enzyme could not cut the modified bond, so small modified two-amino-acid pieces were left.

    Peptide
    Delta sleep-inducing peptide (DSIP)
    Outcome
    Not applicableIsoaspartyl dipeptides as final products
    Study

    n: not reported in source

    In vitro digestion by carboxypeptidase Y
    Outcome group
    Analytical methods and detection · Pharmacology

    Source sentences

    Summary
    Because the isoaspartyl bonds were not cleaved, isoaspartyl dipeptides were among the final products.

    In this study, Delta sleep-inducing peptide (DSIP) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Delta sleep-inducing peptide (DSIP).

  3. 03LabNot a test of Delta sleep-inducing peptide (DSIP) aloneIn vitro (cell-free)Other

    In vitro, a 24-h carboxypeptidase Y digestion of isoaspartyl DSIP yielded 0.50 mol isoaspartylalanine per mol of peptide.

    In plain wordsIn lab tests, 24 hours of enzyme digestion released a fixed amount of a modified two-amino-acid piece from modified DSIP.

    Peptide
    Delta sleep-inducing peptide (DSIP)
    Outcome
    Not applicableRelease of isoaspartylalanine from isoaspartyl DSIP
    Study

    n: not reported in source

    In vitro digestion by carboxypeptidase Y
    Outcome group
    Analytical methods and detection · Pharmacology

    Measurements

    Isoaspartylalanine released
    0.5 mol/mol
    isoaspartyl DSIP, 24-h digestion

    Source sentences

    Summary
    a 24-h digestion yielding 0.32 mol of isoaspartylglycine/mol of isoaspartyl sperm-activating peptide, 0.50 mol of isoaspartylalanine/mol of isoaspartyl delta sleep-inducing peptide

    In this study, Delta sleep-inducing peptide (DSIP) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Delta sleep-inducing peptide (DSIP).

  4. 04LabNot a test of Delta sleep-inducing peptide (DSIP) aloneIn vitro (cell-free)Other

    In vitro, isoaspartyl dipeptides were not detected in carboxypeptidase Y digests of the aspartate- or asparagine-containing forms of the peptides.

    In plain wordsIn lab tests, the modified two-amino-acid pieces did not appear when the unmodified forms were digested.

    Peptide
    Delta sleep-inducing peptide (DSIP)
    Outcome
    Not applicableIsoaspartyl dipeptides in digests of aspartate or asparagine forms
    Study

    n: not reported in source

    In vitro digestion by carboxypeptidase Y
    Outcome group
    Analytical methods and detection · Pharmacology

    Source sentences

    Summary
    Isoaspartyl dipeptides were not detected in digests of the corresponding aspartate- or asparagine-containing forms of the peptides.

    In this study, Delta sleep-inducing peptide (DSIP) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Delta sleep-inducing peptide (DSIP).

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    9 Oct 2026, 18:17 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 03:04 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

PepBank is a research reference. Talk to a doctor before you use any peptide.