Taraxalisin – a serine proteinase from dandelion Taraxacum officinale Webb s.l

Abstract

Latex of dandelion roots contains a serine proteinase that hydrolyzes a chromogenic peptide substrate Glp-Ala-AlaLeu-pNA optimally at pH 8.0. Maximal activity of the proteinase in the roots is attained in April, at the beginning of plant development after the winter period. The protease was isolated by ammonium sulfate precipitation of the root extract followed by affinity chromatography on a Sepharose-Ala-AlaLeu-mrp and gel filtration on Superose 6R performed in FPLC regime. Pure serine proteinase named taraxalisin was inactivated by specific inhibitors of serine proteinases, diisopropylfluorophosphate (DFP) and phenylmethylsulfonylfluoride (PMSF). Its molecular mass is 67 kDa and pI 4.5. pH stability range is 6^9 in the presence of 2 mM Ca P+ , temperature optimum is at 40³C; K m =0.37 þ 0.06 mM. The substrate specificity of taraxalisin towards synthetic peptides and insulin B-chain is comparable with that of two other subtilisin-like serine proteinases, cucumisin and macluralisin. The taraxalisin N-terminal sequence traced for 15 residues revealed 40% coinciding residues when aligned with that of subtilisin Carlsberg.z 1998 Federation of European Biochemical Societies.

Potential of laticifer fluids for inhibiting Aedes aegypti larval development: evidence for the involvement of proteolytic activity

“…Serine and EC 3.4.22 have been reported as the most common proteinases found in laticifer fluids and the latter was largely predominant in the materials tested in the present paper, in which three out of four latex fluids analysed showed proteolytic activity. Plant EC 3.4.22 play major roles in intracellular and extracellular processes such as the development and ripening of fruits (Brady 1985), the building of nutritional reserves, the degradation of storage proteins in germinating seeds (Kembhavi et al 1993, Taylor & Cuming 1993, the activation of pro-enzymes and the degradation of defective proteins (Rudenskaya et al 1998). Additionally, enzymes in latex are involved protecting the plant against predator attack (Smith et al 1955, Boller 1986).…”

LeSBT1, a Subtilase from Tomato Plants

“…were found to accept a broad range of substrates, and each cleaved the insulin B chain at eight different positions (8,9,11). Taraxalisin, a serine proteinase from dandelion that likely belongs to the subtilase family, hydrolyzed nine peptide bonds within the oxidized insulin B chain (10). Therefore, in contrast to hitherto described plant subtilases, LeSBT1 is not likely to serve a degradative function but may be involved in selective protein processing, as are the PCs and the pyrolysins SKI-1 and S1P in animals (2,3,19,20).…”

“…While LeSBT1 exhibited preference for Gln in the P 1 position of its substrate, this residue was not absolutely required. Cleavage of glucagon-(1-24) to yield glucagon- (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) indicates that Asp is tolerated in the P 1 position. However, cleavage carboxylterminal of Asp and accumulation of glucagon-(1-15) was slow except at pH 4.5 to 4.0 (Fig.…”

An overview and economical importance of few selected endangered medicinal plants grown in Jammu and Kashmir region of India

“…The other lactones isolated and identified are 11 -dihydrolactucin, ixerin D and ainslioside (Kisiel et al, 2000). Taraxalisin-a serine proteinase isolated from latex of roots of Taraxacum officinale (Rudenskaya et al, 1998). Three flavonoid glycosides: luteolin 7-glucoside and two luteolin 7-diglucosides isolated from dandelion flowers and leaves together with free luteolin and chrysoeriol in the flower tissue.…”