Purification and characterization of lipoxygenase from mung bean (Vigna radiata L.) germinating seedlings

Abstract

This study reports purification and characterization of lipoxygenase protein from mung bean germinating seedlings. Lipoxygenases (LOXs) are key enzymes in seed germination. The purified mung bean LOX has resolved into two peaks by chromatofocusing, one has highest LOX activity with an isoelectric point of 5.84 and the other has lowest LOX activity with an isoelectric point of 5.52. The purified LOX has molecular mass of approximately 97 kDa and showed high activity with linoleic acid than linolenic acid and arachidonic acid. The optimal activity of LOX was observed at pH 6.5 and temperature 35 °C. Far-UV circular dichroism (CD) studies revealed that the purified mung bean LOX possess secondary structural elements with significant α-helix and β-strands. Further, the secondary structure of mung bean LOX was stable up to 60 °C at pH 6.5. Biophysical and chemical properties of the mung bean LOX are similar to the other legume LOXs and may be considered as type-1 LOX.

Effect of Processing on Mungbean (Vigna radiata) Flour Nutritional Properties and Protein Composition

“…These included enzymes involved in starch degradation and carbon metabolism, including alpha-1,4 glucan phophorylase, UTP-glucose-1-phosphate uridylyltransferase, fructose-bisphosphate aldolase and ATPase (subunit 1). The other two enzymes included seed linoleate 9S-lipoxygenase, involved in fatty acid metabolism (Aanangi et al, 2016) and nudix hydrolase 3-like, which is involved in hydrolysis of a wide range of organic pyrophosphates and has been implicated to play a role in germination of Arabidopsis (Zeng et al, 2014). Other enzymes involved in metabolism, detected only in MGF (Appendix B), were glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase, fructokinase-2-like and enolase.…”

Legume lipoxygenase: Strategies for application in food industry

“…However, owing to the low molar absorptivity of the reaction products, the determination of low specific activity preparations is still susceptible to interference by protein absorption. This method has been widely used in recent studies of legume LOX including pea (Akyol, Alpas, & Bayındırlı, 2006;Leone et al, 2001;Szymanowska et al, 2009), mung bean seeds (Aanangi et al, 2016), and soybean and soy product (Jiang et al, 2018;Manassero, Vaudagna, Sancho, Añón, & Speroni, 2016;Tedjo, Eshtiaghi, & Knorr, 2000).…”

“…The optimum pH for green pea seed LOX was found to be 5.0-7.0 (Szymanowska et al, 2009). According to Aanangi et al (2016), mung bean LOX has the highest activity at pH 6.5. Considerable LOX activity was noted within a pH range 4.5-8.0, but mung bean LOX activity was reduced 50% in the pH below 4.5 or above 8.0.…”

“…LOXs are a group of nonheme iron, nonsulfur iron, or manganesecontaining dioxygenase redox enzymes (Aanangi et al, 2016), which are widely distributed in plant and animal cells. LOX can specifically catalyze polyunsaturated fatty acids (PUFAs) and esters with cis-and cis-pentadiene structure, and hydroperoxide derivatives with conjugated double bonds are formed by intramolecular oxygen addition.…”

“…LOX has a molecular weight of 93 kDa (Szymanowska, Jakubczyk, Baraniak, & Kur, 2009), and the molecular mass of mung bean LOX is approximately 97 kDa (Aanangi et al, 2016). The molecular weight of soybean LOX is about 94-97 kDa.…”