• Journal of Plant Biology
• /
• v.25 no.2
• /
• pp.73-81
• /
• 1982

The changes in activities of glyoxysomal and peroxisomal enzymes during the transition from fat degradation to photosynthesis were investigated with the cotyledns of rape (Brassica napus L.) seedlings. The development and disappearance of glyoxysomal enzyme (isocitrate lyase, EC 4.1.3.1; malate dehydrogenase, EC 1.1.1.37; catalase, EC 1.11.1.6) activities took place independently of light. It is concluded that the mobilization of storage fat is independent of photomorphogenesis. During early periods of development in the dark of light (days 1 through 3), the glyoxysomal enzyme activities were relatively high and the enzyme activities rose to a peak at 3rd day after sowing. Thereafter, the activities decreased gradually. While glyoxysomal enzyme activities were dropping, the peroxisomal enzyme (glycolate oxidase, EC 1.1.3.1) activities were increasing rapidly during the transition period in the light. Moreover, the changes of enzyme activities of the common microbody marker, catalase, indicated both functional patterns. The enzyme patterns in rape cotyledons indicate that the glyoxysomal function of microbodies is replaced by the peroxisomal function of these organelles during the transition from fat degradation to photosynthesis.

• Journal of the Korean Chemical Society
• /
• v.37 no.12
• /
• pp.1068-1075
• /
• 1993

Catalase activities were assayed on the leaves and roots of Tomato (Lycopersicum esculentum) as a function of age for 1 year after germination. The enzyme activities of root tissue demonstrated to be insignificant through all stages of development. On the other hand, the catalase activities of leaf peroxisomal fractions showed remarkable changes with peak value of 76 ${\mu}mol$/ml/min at germination stage within 2 weeks growth, 7.2 ${\mu}mol$/ml/min at adult stage around 4∼5 months growth and very small activities at aged period around 11∼12 months growth. It is suggested that there may be two factors concerning such catalase activities in relation with age, firstly the glyoxisomal reactions including glyoxylate cycle and $\beta$-oxidation at germination stage and secondly photosynthesis hereafter seemed to affect age dependent changes of catalase activity by producing coincident amount of $H_2O_2$. In addition, NADPH coenzyme was found to have ability to restore catalytic acitivity of inactivated catalase (compound II) at all stages of development except old age, indicating NADPH would play a role as catalase protector against deleterious substrate,$H_2O_2$.

• Journal of Nutrition and Health
• /
• v.26 no.7
• /
• pp.887-898
• /
• 1993

In order to determine the effect of iron depletion and subsequent supplementation on the muscle capacity for peroxisomal (PO) and mitochondrial(MO) $\beta$-oxidation during high fat feeding, weanling rats were fed a 44% (HF) or 2.5% (LF) fat diet with (+Fe) or without (-Fe) iron for 6 or 9 weeks. After 1 week rats fed HF+Fe or HF-Fe had 50-100% more PO and MO in heart, soleus, psoas and gastrocnemius than did rats fed low fat, but after 3 weeks rats fed HF-Fe had lower muscle PO and MO. In muscles of iron depleted rats PO and MO were not increased by supplementation with iron for 3 weeks. After 6 weeks MO and PO in skeletal muscles of rats fed HF+Fe were lower than after 3 weeks. It is concluded that adequate iron is necessary for miaximum response of muscle PO and MO to high fat feeding. However, after 6 weeks both PO and MO have returned to levels similar to those of rats fed low fat diets, hence, the elevated catalase activities seen at this time do not reflect peroxisomal $\beta$-oxidation.

• Journal of Nutrition and Health
• /
• v.34 no.8
• /
• pp.858-864
• /
• 2001

The study was designed to observe an antioxidant activities of conjugated linoleic acid(CLA) in rat liver by determining the activities of antioxidative enzymes(superoxide dismutase, glutathione peroxidase, catalase) and the levels of tocopherol and thiobarbituric acid reactive substance(TBARS). Male Sprague Dawley rats at weeks-old were divided into groups according to the types of dietary fat(beef tallow and fish oil) and then each group was subdivided into groups depending on CLA supplement. All rats were fed experimental diet containing 12% total fat including 1% CLA by weight for 30 weeks. CLA supplemented to beef tallow diet did not have significant effect on the level of TBARS and tocopherol. The level of TBARS was significantly increased in fish oil diet(highly unsaturated fat diet), but its level was significantly reduced by increasing SOD and GSH-Px activities when CLA was supplemented to fish oil diet so that CLA showed a sparing action of tocopherol in tissue. CLA did not have significant effect on peroxisomal catalase activities, but its activity was significantly increased when TBARS production was high in the fish oil diet. CLA could be incorporated into phospholipid of microsomal membrane, and interfered the conversions of C18 : 0 into C18 : 1 and C18 : 2 into C20 : 4 in liver. In conclusion, CLA had an antioxidant activities depending on the type of fat in diet. Therefore, it could be recommended to use CLA when highly unsaturated fat was used in meal preparation.

• Journal of Plant Biology
• /
• v.27 no.4
• /
• pp.241-251
• /
• 1984

The present study investigated the effects of triacontanol (TRIA) on plant growth and peroxisomal enzyme activities in radish seedlings. The optimum concentration of TRIA with respect to radish seedling bioassay was decided to 1.0mg $1^{-1}$. In comparison to untreated controls (including Tween 20 treatment), 1.0mg $1^{-1}$ TRIA treatment caused an increase in seed germination rate and root growth, but no stimulation in hypocotyl growth. Chlorophyll accumulation in cotyledon during carly development stage increased rapidly, and degradation of chlorophyll in later stage due to the cotyledon senesence was noticeably retarded. Increase of soluble protein content in cotyledon at early period of development was observed. Isocitrate lyase and catalase activity was not significantly different in both the treated and the untreated plants. But, glycolate oxidase activity was inhibited by TRIA down to 20% against controls. Also, the increase of the activity of peroxidase, a leaf-senescence marker enzyme, was continuously retarded over control for 8 days of development. Based on above results, TRIA was found to be active in both the growth and the peroxisomal enzyme activities of radish seedlings.

• Journal of Plant Biology
• /
• v.31 no.3
• /
• pp.197-203
• /
• 1988

The rates of photorespiration and total CO2 fixation depending on leaf ages of spinach (Spinacia oleracea L.) were investigated. Metabolic rates of glycolate and glyoxylate in isolated peroxisomes were also measured. The rate of photorespiration and total CO2 fixation ability increased with the maturing of leaf, but decreased with senescence. Activities of enzymes involved in the peroxisomal photorespiratory pathway such as catalase, glycolate oxidase, NADH-glyoxylate reductase and glutamate-glyoxylate transaminase were highest in the mature leaf, but also decreased with aging of leaf. Glutamate-glyxolate transaminase activity significantly decreased with senescence, especially. the metabolic rate of glycolate was observed to be lower than that of glyoxylate in isolated peroxisomes. Glycolate seemed to be metabolized mainly to glycine, however, it also oxidized to CO2 when glycolate was supplied as a substrate for glycine synthesis instead of glyoxylate. The conversion rates of glycolate and glyxylate into CO2 increased with the senescence of leaves.

• Molecules and Cells
• /
• v.38 no.2
• /
• pp.187-194
• /
• 2015

Thioredoxin (TRX) is a disulfide reductase present ubiquitously in all taxa and plays an important role as a regulator of cellular redox state. Recently, a redox-independent, chaperone function has also been reported for some thioredoxins. We previously identified nodulin-35, the subunit of soybean uricase, as an interacting target of a cytosolic soybean thioredoxin, GmTRX. Here we report the further characterization of the interaction, which turns out to be independent of the disulfide reductase function and results in the co-localization of GmTRX and nodulin-35 in peroxisomes, suggesting a possible function of GmTRX in peroxisomes. In addition, the chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including the thermal denaturation assay and malate dehydrogenase aggregation assay. Our results demonstrate that the target of GmTRX is not only confined to the nodulin-35, but many other peroxisomal proteins, including catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), and acyl-coenzyme A oxidase 4 (AtACX4), also interact with the GmTRX. Together with an increased uricase activity of nodulin-35 and reduced ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin that is co-localized to the peroxisomes, possibly providing functional integrity to peroxisomal proteins.

• Journal of Life Science
• /
• v.33 no.8
• /
• pp.651-662
• /
• 2023

Peroxisomes, known as microbodies, are a class of morphologically similar subcellular organelles commonly found in most eukaryotic cells. They are 0.2~1.8 ㎛ in diameter and are bound by a single membrane. The matrix is usually finely granular, but occasionally crystalline or fibrillary inclusions are observed. They characteristically contain hydrogen peroxide (H₂O₂) generating oxidases and contain the enzyme catalase, thus confining the metabolism of the poisonous H₂O₂ within these organelles. Therefore, the eukaryotic organelles are greatly dynamic both in morphology and metabolism. Plant peroxisomes, in particular, are associated with numerous metabolic processes, including β-oxidation, the glyoxylate cycle and photorespiration. Furthermore, plant peroxisomes are involved in development, along with responses to stresses such as the synthesis of important phytohormones of auxins, salicylic acid and jasmonic acids. In the past few decades substantial progress has been made in the study of peroxisome biogenesis in eukaryotic organisms, mainly in animals and yeasts. Advancement of sophisticated techniques in molecular biology and widening of the range of genomic applications have led to the identification of most peroxisomal genes and proteins (peroxins, PEXs). Furthermore, recent applications of proteome study have produced fundamental information on biogenesis in plant peroxisomes, together with improving our understanding of peroxisomal protein targeting, regulation, and degradation. Nonetheless, despite this progress in peroxisome development, much remains to be explained about how peroxisomes originate from the endoplasmic reticulum (ER), then assemble and divide. Peroxisomes perform dynamic roles in many phases of plant development, and in this review, we focus on the latest progress in furthering our understanding of plant peroxisome functions, biogenesis, and dynamics.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.8
• /
• pp.1162-1167
• /
• 2004

The present study was designed to define whether dietary conjugated linoleic acid (CLA) could affect antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and glutathione S transferase (GST), and the level of malondialdehyde (MDA), a marker of lipid peroxidation, in the small intestine and liver from broiler chickens. A total of twenty-four 3 wk-old male broiler chickens were assigned to three dietary treatments (1.5% corn oil, 0.75% corn oil plus 0.75% CLA, and 1.5% CLA, isocalorically), and fed a grower-finisher diet from 22 to 35 days. In the small intestinal mucosae, the specific activities of SOD, GSH-Px, CAT, and GST, and the level of MDA were not substantially influenced by dietary CLA. In the liver, the specific activities of SOD, GSH-Px, and GST, and the level of MDA were also unaffected by dietary CLA at the level of either 0.75% or 1.5% compared with corn oil at the level of 1.5%. However, the broiler chickens fed the diet containing 1.5% CLA resulted in a significant increase in peroxisomal CAT activity and a marked decrease in total lipid and non-esterified fatty acids (NEFA) from liver tissues compared with those fed the diet containing 1.5% corn oil. In conclusion, ability of CLA to increase hepatic CAT activity suggest that dietary CLA may affect, at least in part, antioxidant defense system as well as lipid metabolism in the liver of broiler chickens.