Soybean cystatin

Glycine max (soybean) (Fabaceae) [seed] Soybean cystatin SC (245 aa 27 kDa 1 Cys homologue of 11 kDa phytocystatins plus N- C-terminal extensions) Papain (10-100 nM IC50 for SC SC constructs devoid of N-terminal or C-terminal extension or both extensions) [162]... 

Figure B3.1.3 An isoelectric focusing (IEF) gel, pH 3 to 10. Lane 1, 4 pg purified egg white cystatin. Lane M, broad-range pi standards trypsinogen (pi 9.3), lentil lectin-basic band (pi 8.65), lentil lectin-middle band (pi 8.45), lentil lectin-acidic band (pi 8.15), myoglobin-basic band (pi 7.35 visible as a broad band), myoglobin-acidic band (pi 6.85), human carbonic anhydrase B (pi 6.55), bovine carbonic anhydrase (pi 5.85), a-lactoglobulin A (pi 5.20), soybean trypsin inhibitor (pi 4.55), and amyloglucosidase (pi 3.50) in order shown from top of gel. The pi values of the two purified egg white cystatin isomers were determined to be 6.6 (upper band) and 5.8 (lower band). Adapted from Akpinar (1998) with permission from author.

A family of cysteine proteinase inhibitors different from the cystatin super-family was Isolated from pineapple stem acetone powder. These inhibitors have a Mr of about 5800 and are composed of a longer (41 amino acids) and a shorter (1L ammo acids) peptide chain connected with disulfide bonds [29]. The conserved sequence Gin- fal-Val-AJa-Gly of the cystatins is not present in these inhibitors, indicating a different mechanism of interaction. The bromelain inhibitor VI was found to share similar folding and disulfide band connectivities with the Bowman-Bilk trypsiu/chymatrypsm inhibitor from soybean [30,31]. Hie physiological role of these inhibitors remains undear. 

Chelidonium Chelidostatin (10 kDa phytocystatin) Daucus phytocystatin EIP18 (18 kDa phytocystatin) Glycine Cystatins LI, N2 (Soyacystatin scN soybean CYSPR inhibitor N), R1 (11 kDa phytocystatins) Heliantkus phytocystatins Sea, Scb (10 kDa phytocystatins) Hordeum Lipid Transfer Proteins 1 2 (= LTP 1 2) (7 kDa protein)... 

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