scholarly journals Parameters for Use of Waste Castor-Oil Seed (Ricinus communis) as Biomass

2019 ◽  
pp. 1-8
Author(s):  
Javier E. Rodríguez-Yáñez
Keyword(s):  
Castor Oil ◽  
Ricinus Communis ◽  
Oil Seed

scholarly journals Disulfide formation in plant storage vacuoles permits assembly of a multimeric lectin

2010 ◽  
Vol 427 (3) ◽  
pp. 513-521 ◽  
Author(s):  
Richard S. Marshall ◽  
Lorenzo Frigerio ◽  
Lynne M. Roberts
Keyword(s):  
Disulfide Bond ◽  
Disulfide Bonds ◽  
Castor Oil ◽  
Ricinus Communis ◽  
Bond Formation ◽  
Disulfide Bond Formation ◽  
Endosperm Tissue ◽  
Oil Seed ◽  
Protein Storage Vacuole ◽  
Protein Disulfide

The ER (endoplasmic reticulum) has long been considered the plant cell compartment within which protein disulfide bond formation occurs. Members of the ER-located PDI (protein disulfide isomerase) family are responsible for oxidizing, reducing and isomerizing disulfide bonds, as well as functioning as chaperones to newly synthesized proteins. In the present study we demonstrate that an abundant 7S lectin of the castor oil seed protein storage vacuole, RCA (Ricinus communis agglutinin 1), is folded in the ER as disulfide bonded A–B dimers in both vegetative cells of tobacco leaf and in castor oil seed endosperm, but that these assemble into (A–B)2 disulfide-bonded tetramers only after Golgi-mediated delivery to the storage vacuoles in the producing endosperm tissue. These observations reveal an alternative and novel site conducive for disulfide bond formation in plant cells.

scholarly journals Kinetic and regulatory properties of cytosolic pyruvate kinase from germinating castor oil seeds

1991 ◽  
Vol 279 (2) ◽  
pp. 495-501 ◽  
Author(s):  
F E Podestá ◽  
W C Plaxton
Keyword(s):  
Pyruvate Kinase ◽  
Castor Oil ◽  
Mixed Type ◽  
Competitive Inhibition ◽  
Ricinus Communis ◽  
Cytosolic Ph ◽  
Oil Seeds ◽  
Saturation Kinetics ◽  
Regulatory Properties

The kinetic and regulatory properties of cytosolic pyruvate kinase (PKc) isolated from endosperm of germinating castor oil seeds (Ricinus communis L.) have been studied. Optimal efficiency in substrate utilization (in terms of Vmax/Km for phosphoenolpyruvate or ADP) occurred between pH 6.7 and 7.4. Enzyme activity was absolutely dependent on the presence of a bivalent and a univalent metal cation, with Mg2+ and K+ fulfilling this requirement. Mg2+ binding showed positive and negative co-operativity at pH 6.5 (h = 1.6) and pH 7.2 (h = 0.69) respectively. Hyperbolic saturation kinetics were observed with phosphoenolpyruvate (PEP) and K+, whereas ADP acted as a mixed-type inhibitor over 1 mM. Glycerol (10%, v/v) increased the S0.5(ADP) 2.3-fold and altered the pattern of nucleotide binding from hyperbolic (h = 1.0) to sigmoidal (h = 1.79) without modifying PEP saturation kinetics. No activators were identified. ATP, AMP, isocitrate, 2-oxoglutarate, malate, 2-phosphoglycerate, 2,3-bisphosphoglycerate, 3-phosphoglycerate, glycerol 3-phosphate and phosphoglycolate were the most effective inhibitors. These metabolites yielded additive inhibition when tested in pairs. ATP and 3-phosphoglycerate were mixed-type inhibitors with respect to PEP, whereas competitive inhibition was observed for other inhibitors. Inhibition by malate, 2-oxoglutarate, phosphorylated triose sugars or phosphoglycolate was far more pronounced at pH 7.2 than at pH 6.5. Although 32P-labelling studies revealed that extensive phosphorylation in vivo of soluble endosperm proteins occurred between days 3 and 5 of seed germination, no alteration in the 32P-labelling pattern of 5-day-germinated endosperm was observed after 30 min of anaerobiosis. Moreover, no evidence was obtained that PKc was a phosphoprotein in aerobic or anoxic endosperms. It is proposed that endosperm PKc activity of germinating castor seeds is enhanced after anaerobiosis through concerted decreases in ATP levels, cytosolic pH and concentrations of several key inhibitors.

Castor Oil ( Ricinus communis )

2022 ◽  
pp. 51-78
Author(s):  
Is Fatimah ◽  
Suresh Sagadevan ◽  
Baranya Murugan ◽  
Oki Muraza
Keyword(s):  
Castor Oil ◽  
Ricinus Communis
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