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Symptom
Drug
Enzyme
Compound
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Target Concepts:
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Query: UNIPROT:P01189 (
beta-endorphin
)
21,003
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Highly purified calf brain
cathepsin D
(EC 3.4.23.5) selectively splits the Leu77-Phe78 and Ala36-Ala37 peptide bonds of human beta-lipotropin. It is suggested that the formation of human "beta-melanotropin" from gamma-lipotropin, and that of
gamma-endorphin
from
beta-endorphin
, is due to the action of
cathepsin D
during isolation procedures.
...
PMID:Action of cathepsin D on human beta-lipotropin: a possible source of human "beta-melanotropin". 29 8
gamma-Endorphin is a naturally occurring biologically active peptide that is produced by an endopeptidase activity cleaving its precursor
beta-endorphin
. This enzyme was termed
gamma-endorphin
generating enzyme (gamma-EGE). In order to quantitate gamma-EGE activity by means of a simple and sensitive assay two synthetic peptides derived from the sequence surrounding the gamma-EGE cleavage site in
beta-endorphin
were tested as substrates. One of these peptides Ac-Val-Thr-Leu-Phe-Lys-NHCH3 fulfilled all criteria for a suitable gamma-EGE substrate. The peptide was exclusively cleaved at the correct bond for gamma-EGE upon incubation with brain synaptic membranes, and this cleavage was inhibited by the naturally occurring substrate
beta-endorphin
. The peptide was insensitive to cleavage by exopeptidases and
cathepsin D
. Addition of a 14C-labeled methyl group at the lysine residue of this peptide by reductive methylation did not alter its properties as a substrate for gamma-EGE activity. The use of the 14C-labeled peptide allowed sensitive quantitation of its radioactive products after simple separation by hydrophobic chromatography on minicolumns containing polystyrene beads. gamma-EGE activity increased linearly with a protein concentration and incubation time. This assay can be used for reliable quantitation of gamma-EGE activity and permits investigations on the regulation of
gamma-endorphin
production.
...
PMID:Quantitation of the endopeptidase activity generating gamma-endorphin from beta-endorphin in rat brain synaptic membranes by a radiometric assay. 620 8
Tonin, a proteolytic enzyme isolated from rat submaxillary gland, was allowed to react upon ovine beta-lipotropin (
beta-LPH
) at 37 degrees C at a variety of pH values and for different lengths of time. Opiatelike activity generated by the reaction was assessed using a radioreceptor assay for
beta-endorphin
with rat brain homogenate. [3H]naloxone, and
beta-endorphin
as receptors, tracer, and hormone standard, respectively. Cleavage of
beta-LPH
with tonin produced a 10-fold increase in opiatelike activity as compared with
beta-LPH
alone. Digestion of
beta-LPH
with other enzymes such as renin,
cathepsin D
, trypsin, and chymotrypsin produced much less opiatelike activity. beta-Endorphin and methionine-enkephalin were not cleaved by tonin. Using this new assay, we were able to detect
beta-LPH
and materials containing opiatelike activity from rat pituitary extracts after gel chromatography. It is more specific and more sensitive than trypsin digest.
...
PMID:Detection from rat pituitary of beta-lipotropin and materials containing opiatelike activity by combined enzymatic radioreceptor assay. 627 75
Cathepsin D
(EC 3.4.3.23) purified from human putuitary by affinity chromatography on pepstatin-Sepharose cleaved human
beta-endorphin
(LPH 61-91) at the Leu(77)-Phe(78) bond after incubation at pH 3.2 for 1-3. Incubation with smaller lipotropic fragments (enkephalin, alpha-endorphin,
gamma-endorphin
) did not lead to further degradation. Cleavage sites were identified following the separation of danyslated or iodinated peptides on polyamide sheets accompanied by N-group determination, or following slab-gel electrophoresis of the iodinated peptides. Cleavage at the above site was blocked using an analog containing D-Leu(77). Breakdown of porcine beta-lipotropin (LPH 1-91) was slower and required an 18 h incubation. A product LPH 1-77 was tentatively identified based in part on its mobility on slab gels as compared to
beta-LPH
and beta-endophine and by N-group determination of cleavage products.
...
PMID:Conversion of lipotropic peptides by purified cathepsin D of human pituitary: release of gamma-endorphin by cleavage of the Leu(77)-PHE(78) bond. 1960 48
