Use of methionine-enkephalin sulfoxide and leucine-enkephalin radio-immunoassays for the measurement of enkephalins in the rat brain.
1. A radio-immunoassay (RIA) for methionine-enkephalin sulfoxide was developed and was used to measure methionine-enkephalin, after oxidation, in the rat brain. 2. The RIA was performed together with assays that use commercially available met- and leu-enkephalin antisera. 3. Evidence is presented here indicating that antisera raised against the native met-enkephalin peptide underestimate met-enkephalin content due to loss of immunoreactivity after oxidation of peptide. 4. These results show that a more accurate measurement of met-enkephalin may be obtained by using the met-enkephalin sulfoxide RIA. The cross-reactivity of met-enkephalin with the leu-enkephalin RIA was diminished following oxidation of peptide.
Tiong
G K
GK
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Olley
J E
JE
D000818:Animals; D001923:Brain Chemistry; D003429:Cross Reactions; D004743:Enkephalin, Leucine; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000032:analysis*; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives*; D011863:Radioimmunoassay; D051381:Rats
D004745:Enkephalins; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D008715:Methionine; C013111:methionine sulfoxide