Note: a dashed line (without arrowheads) between two compound names is meant to imply that the two names are just different instantiations of the same compound -- i.e. one may be a specific name and the other a general name, or they may both represent the same compound in different stages of a polymerization-type pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Locations of Mapped Genes:
|Superclasses:||Degradation/Utilization/Assimilation → Protein Degradation|
Pathway Summary from MetaCyc:
The presence of two different peptidases have been reported both in swine intestinal mucosa and in germinating Hordeum vulgare (barley) grains; one of the enzymes liberated N-terminal leucine from a L-leucine-glycine-glycine tripeptide with a pH optimum of 8.6, the other hydrolyzed the dipeptide L-alanine-glycine with a pH optimum at 7.8 [Sopanen75].
Similar enzyme activities such as hydrolysis of L-leucine-glycine-glycine or L-leucine-NH, at pH 8-10, have also been detected in the leaves of spinach and cabbage [Berger39], and in the germinating seeds of Pinus pinea L. [Guitton63] and Cucurbita maxima L. [Ashton67]. However, only the barley enzyme has been purified and characterized.
This barley enzyme is different from the various other known barley peptidases [Mikola72] and is remarkably similar to mammalian and bacterial leucine aminopeptidases. [Mikola72] reported that L-leucine-L-tyrosine hydrolyzing activity is present in all living tissues of germinating Hordeum vulgare seeds: the aleurone layer of the endosperm, the scuttellum, and the growing tissues of the seedling. Corresponding activity has been detected in several other plants, including both dicots and a gymnosperm (Pinus pinea L.).
Pathway Evidence Glyph:
Key to pathway glyph edge colors:
An enzyme catalyzing this reaction is present in this organism
The reaction and any enzyme that catalyzes it (if one has been identified) is unique to this pathway
Represents spontaneous reactions, or lines that do not represent reactions (e.g. in polymerization pathways)
Guitton63: Guitton, Y, De Belsunce, M (1963). "[Nitrogen metabolism of the Gymnosperms. Evidence for a leucine aminopeptidase in the seeds and young plantlets of Pinus pinea L.] (French)." C.R. Hebd. Seances Acad. Sci. 256, 2689-2691.
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