Radiochromatographic assay of metabolites of the oostatic peptide labeled in different positions of the peptide chain.
Reversed-phase high-performance liquid radio-chromatography (radio-HPLC) was set up to detect the time course of labeled degradation product formation of the pentapeptide H-Tyr-Asp-Pro-Ala-Pro-OH (5P), which has oostatic effects in different insect species. The detection limit of the system was in the range of 80-150 Bq. To follow formation of the degradation products, three amino acid residues in 5P were independently tritiated: Tyr1, Pro3 and Pro5. Each of the three tritiated peptides was analyzed after incubation with fresh hemolymph or ovaries of Neobellieria bullata. In the incubation mixture, free terminal amino acids and shortened sequences of 5P were identified. A metabolite of tyrosine represented the only exception; it was finally identified as water using degradation of [3H]Tyr by tyrosinase. Metabolic degradation of [3H]Tyr-5P was found to be considerably quicker than that of H-[3H]Tyr-Asp-Pro-Ala-OH (4P). The degradation of 5P was considerably slower in ovaries in comparison to hemolymph.
Tykva
Richard
R
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo sq. 2, 166 10 Prague 6, Czech Republic.
Hlavácek
Jan
J
Vlasáková
Vera
V
Cerný
Bohuslav
B
Borovicková
Lenka
L
Bennettová
Blanka
B
Holík
Josef
J
Slaninová
Jirina
J
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004175:Diptera / Q000378:metabolism; D005260:Female; D006458:Hemolymph / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism* / Q000493:pharmacokinetics / Q000592:standards; D010053:Ovary / Q000378:metabolism; D012015:Reference Standards; D015203:Reproducibility of Results; D014316:Tritium; D014443:Tyrosine / Q000378:metabolism
D009842:Oligopeptides; D014316:Tritium; C065612:Peptide oostatic hormone; D014443:Tyrosine