Partial purification and characterization of the quality deteriorating enzymes from Indian pink guava (Psidium guajava L.), var. Lalit

Abstract

Peroxidase (POD), polyphenol oxidase (PPO), ascorbate oxidase (AO) and pectin methylesterase (PME) from 'Lalit' guava variety have been purified using BioGel P-100 and UNOsphere Q resins. POD, PPO, AO, and PME were partially purified to 28, 30, 36 and 30 fold; single band on SDS-PAGE represented a molecular weight of 21, 70, 75, 50 kDa, respectively. Optimum pH for POD and AO was 6.5 whereas, PPO and PME showed optimum pH in the alkaline range of pH 8.0 and 8.5, respectively. AO showed optimum activity at 25 °C, POD and PPO showed optimum activity at 35 °C; however, PME showed maximum activity at 55 °C. AO was the most heat labile whereas, PME was the most heat stable enzyme studied and may carry an important role in the thermal processing of guava pulp as an indicator of the efficacy of treatment.

Purification, kinetic parameters, and isoforms of polyphenol oxidase from “Xushu 22” sweet potato skin

“…In contrast, the yield of sPPO2 was 2.10%, and the sPPO2 specific activity was 53,463.16 U/mg. Compared to previous literature reports, the fold-purification was 5.14 higher than reported for the PPO from potato (Aksoy, 2020), 19.77-fold higher than for the PPO from tea leaf (Camellia sinensis) (Öztürk, Aksoy, & Küfrevioğlu, 2019), 13.3 and 22.5 than for the PPO from Ginseng (Kim & Kim, 2013), and 12.38 higher than for the PPO from Indian pink guava (Vishwasrao & Ananthanarayan, 2018). The recovery rate was higher than for the PPO from mamey fruit (Pouteria sapota) which was 0.28% (Orozcoa, Moreno, Álvarez, Sampedrob, & Nájerac, 2011) and close to the recovery rate of 2.03% seen for the PPO from chestnut kernel (Gong, Li, Liu, Cheng, & Wang, 2015) and 3 Based on the Superdex-200 gel filtration analysis the native molecular weights for sPPO1, sPPO2, and mPPO were estimated to be 182.97, 205.12, and 174.98 kDa (Figure 2c) suggesting the all three isoforms exist as tetramers in the native state, which was consistent with the PPO from Iceberg Lettuce (Lactuca sativa L.) (Chazarra, García-Carmona, & Cabanes, 2001), Satsuma mandarine (Cheng et al, 2014), pineapple fruit (Das, Bhat, & Gowda, 1997), dandelion (Hofmeister, Inlow, & Moerschbacher, 2012), and field bean seed (Paul & Gowda, 2000).…”

“…In contrast, the yield of sPPO2 was 2.10%, and the sPPO2 specific activity was 53,463.16 U/mg. Compared to previous literature reports, the fold‐purification was 5.14 higher than reported for the PPO from potato (Aksoy, 2020), 19.77‐fold higher than for the PPO from tea leaf ( Camellia sinensis ) (Öztürk, Aksoy, & Küfrevioğlu, 2019), 13.3 and 22.5 than for the PPO from Ginseng (Kim & Kim, 2013), and 12.38 higher than for the PPO from Indian pink guava (Vishwasrao & Ananthanarayan, 2018). The recovery rate was higher than for the PPO from mamey fruit ( Pouteria sapota ) which was 0.28% (Orozcoa, Moreno, Álvarez, Sampedrob, & Nájerac, 2011) and close to the recovery rate of 2.03% seen for the PPO from chestnut kernel (Gong, Li, Liu, Cheng, & Wang, 2015) and 3.0% for the PPO from soursop ( Annona muricata L.) (Orozco, Hernández, Tobías, & Nájera, 2019).…”

Kinetics and molecular docking of purified polyphenol oxidase from rhizome of turmeric (Curcuma longa L.)

“…The Km of C. longa PPO was 5.8 ± 0.6mM and Vmax of 722.9 ± 17.0 units/mg protein respectively, while the catalytic e ciency and speci city constant of the puri ed enzymes kcat/Kmwas 1.43x10 5 s -1 M -1 . Lower Km suggests higher a nity towards the substrate [39]. The kinetics revealed useful information about the catalytic mechanism, and mechanisms of inhibition of the puri ed turmeric PPO which would be exploited in several biotechnological processes.…”