Isolation and Partial Characterization of Alcohol Dehydrogenase From Broad Bean (Vicia faba)

1974 ◽  
Vol 1 (4) ◽  
pp. 579 ◽  
Author(s):  
S Leblova
Keyword(s):  
Thermal Stability ◽  
Alcohol Dehydrogenase ◽  
Broad Bean ◽  
Plant Tissues ◽  
Growth Substances ◽  
Ph Optimum ◽  
Alcohol Dehydrogenase Activity ◽  
Km Value ◽  
Thermal Stability Of

Alcohol dehydrogenase isolated from broad bean was found to have a Km value of 1.0 × 1.0 -2 M, a pH optimum of 8.7 and a molecular weight of 60 000 � 5000. The enzyme lost 55 % of its activity after being heated at 55�C, and was totally inactivated at 70°C. Thermal stability of the enzyme was not enhanced by NAD+ or ethanol. The substrate specificity of the enzyme is reported. Cysteine and mercaptoethanol activated the enzyme, whilep-chloromercuribenzoate, Cu2+, Hg2+, B4O72- -, Zn2+ and EDTA inhibited it. The influence of ethanol, acetaldehyde and growth substances on alcohol dehydrogenase activity in germinating broad bean seeds and plant tissues was also studied.

scholarly journals SCREENING DAN KARAKTERISASI PEKTINESTERASE SEBAGAI ENZIM POTENSIAL DALAM KLARIFIKASI SARI BUAH JERUK KEPROK GARUT (Citrus nobilis var.chrysocarpa)

2015 ◽  
Vol 35 (04) ◽  
pp. 422
Author(s):  
Rohula Utami ◽  
Esti Widowati ◽  
Arifah Rahayu
Keyword(s):  
Thermal Stability ◽  
Optimum Temperature ◽  
Citrus Pectin ◽  
Ph Optimum ◽  
Citrus Juice ◽  
Optimum Ph ◽  
Km Value ◽  
Screening Result ◽  
Optimum Ph And Temperature

The objective of this research was screening of pectinesterase (PE) producing bacteria which are potential in clarification of keprok garut citrus juice (Citrus nobilis var microcarpa) and characterization of the resulted pectinesterase (optimum pH and temperature, pH and thermal stability, KM and Vmaks). The screening result showed that enzyme of isolates AR2, AR 4, AR 6, and KK 2 was found to be a potential enzyme for clarification of keprok garut citrus juice. Enzyme pektinesterase of isolates AR 2, AR 4, AR 6, and KK 2 had optimum pH at 8; 7.5; 8.5; and 6.5 and stable at pH 4-9, 4-9, 6-9, and 3-8. The optimum temperature enzyme of isolates AR 2 and AR 6 were 55ºC and that of AR 4 and KK 2 were 60ºC. Enzyme of isolate AR 2 was stable at 30-50ºC and inactive at 80ºC, AR 4 and KK 2 were stable at 30-60ºC and inactive at 90ºC whereas AR6 was stable at 30-60ºC and still wasn’t inactive at 90ºC. KM value of isolates AR 2, AR 4, AR 6, and KK 2 were 0.604; 0.338; 0.971; and 0.392 mg/ml. Vmaks value of isolates AR 2, AR 4, AR 6, and KK 2 were 1.218; 0.826; 0.969; and 1.080 u/ml. Pectinesterase enzyme of isolates KK 2 was found to be the most potential enzyme for clarification of keprok garut citrus juice.Keywords: Clarification, enzyme, keprok garut citrus, pectin, pectinesterase ABSTRAKTujuan dari penelitian ini adalah untuk melakukan screening bakteri penghasil enzim pektinesterase (PE) yang berpotensi dalam proses klarifikasi sari buah jeruk keprok garut (Citrus nobilis var microcarpa) serta mengetahui karakteristik enzim pektinesterase yang dihasilkan (pH optimum, suhu optimum, kestabilan pH dan suhu, serta nilai KMdan Vmaks). Hasil screening didapatkan isolat AR 2, AR 4, AR 6, dan KK 2 sebagai isolat penghasil enzim pektinesterase yang berpotensi dalam proses klarifikasi sari buah jeruk keprok garut. Aktivitas enzim pektinesterase isolat AR 2, AR 4, AR 6 dan KK 2 berturut-turut optimum pada pH 8; pH 7,5; pH 8,5; dan pH 6,5, serta stabil pada pH 4-9, pH4-9, pH 6-9, dan pH 3-8. Suhu optimum enzim pektinesterase isolat AR 2, AR 4, AR 6, dan KK 2 berturut-turut adalah 55ºC, 60ºC, 55ºC, dan 60ºC. Enzim pektinesterase isolat AR 2 stabil pada suhu 30-50ºC dan inaktif pada suhu 80ºC, enzim pektinesterase isolat AR 4 dan KK 2 stabil pada suhu 30-60ºC dan inaktif pada suhu 90ºC, sedangkan enzim pektinesterase isolat AR 6 stabil pada suhu 30-60ºC namun belum inaktif pada suhu 90ºC. Nilai konstanta Michaelis-Menten (KM) enzim pektinesterase isolat AR 2, AR 4, AR 6, dan KK 2 berturut-turut adalah 0,604; 0,338; 0,971; dan 0,392 mg/ml. Sedangkan nilai kecepatan maksimum (Vmaks) enzim pektinesterase isolat AR 2, AR 4, AR6, dan KK 2 berturut-turut adalah 1,218; 0,826; 0,969; dan 1,080 U/ml. Enzim pektinesterase isolat KK 2 memiliki karakteristik yang paling sesuai untuk aplikasi dalam klarifikasi sari buah jeruk keprok garut dibandingkan dengan enzim pektinesterase isolat lainnya.Kata kunci: Enzim, klarifikasi, pektin, pektinesterase, jeruk keprok garut

scholarly journals Preparation and characterization of polyhedral oligomeric silsesquioxane/polystyrene nanocomposites

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Benhong Yang ◽  
Meng Li ◽  
Yun Wu ◽  
Kang Wang
Keyword(s):  
Thermal Stability ◽  
Thermal Property ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
29Si Nmr ◽  
Solution Blending ◽  
Oligomeric Silsesquioxane ◽  
Tga And Dsc ◽  
Thermal Stability Of

AbstractSeveral inorganic/organic nanocomposites were prepared via solution-blending of cage-like octahexyl-polyhedral oligomeric silsesquioxane (Oh-POSS) with polystyrene (PS) in THF solvent. FTIR and 29Si-NMR were employed to characterize the structures of the nanocomposites. SEM pictures showed that the sample films were smooth and no POSS aggregation was observed when POSS content was lower than 1.0 wt%. TGA and DSC were used to investigate the thermal property. The results showed that the incorporation of nanosized Oh-POSS enhanced the thermal stability of PS with low POSS content. When 1.0 wt% of Oh-POSS was incorporated into PS matrix, the Tg and Td increased by 7.7 °C and 8.2 °C, respectively. However, higher POSS contents (>1.0 wt%) would deteriorate the thermal property of the nanocomposites due to the severe congregation of POSS..

Systematic Characterization of Different Quaternary Ammonium Salts to be Used in Organoclays

2012 ◽  
Vol 727-728 ◽  
pp. 1552-1556
Author(s):  
Renata Barbosa ◽  
Dayanne Diniz Souza ◽  
Edcleide Maria Araújo ◽  
Tomás Jefférson Alves de Mélo
Keyword(s):  
Thermal Stability ◽  
Quaternary Ammonium ◽  
Chemical Structure ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Degradation Mechanisms ◽  
Scanning Calorimetry ◽  
Higher Temperature ◽  
Thermal Stability Of

Studies of degradation have verified that the decomposition of some quaternary ammonium salts can begin to be significant at the temperature of about 180 ° C and like most thermoplastics are processed at least around this temperature, the thermal stability of the salt in clay should always be considered. Some salts are more stable than others, being necessary to study the degradation mechanisms of each case. In this work, four quaternary ammonium salts were characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG). The results of DSC and TG showed that the salts based chloride (Cl-) anion begin to degrade at similar temperatures, while the salt based bromide (Br-) anion degrades at higher temperature. Subsequently, a quaternary ammonium salt was chosen to be used in organoclays, depending on its chemical structure and its thermal behavior.

Characterization of Thermal Stability of the Escherichia coli Fapy–DNA Glycosylase

2001 ◽  
Vol 288 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Serguei V. Kuznetsov ◽  
Olga M. Sidorkina ◽  
Jacques Laval ◽  
Anjum Ansari
Keyword(s):  
Escherichia Coli ◽  
Thermal Stability ◽  
Dna Glycosylase ◽  
Thermal Stability Of

Synthesis and Characterization of Some Functional Luminol Derivatives with Aromatic Substituted Groups

2011 ◽  
Vol 197-198 ◽  
pp. 606-609 ◽  
Author(s):  
Ti Feng Jiao ◽  
Yuan Yuan Xing ◽  
Jing Xin Zhou ◽  
Wei Wang
Keyword(s):  
Molecular Structure ◽  
Thermal Stability ◽  
Molecular Structures ◽  
Synthesis And Characterization ◽  
Functional Material ◽  
Aromatic Substituent ◽  
The Difference ◽  
Imide Group ◽  
Thermal Stability Of

Some functional luminol derivatives with aromatic substituted groups have been designed and synthesized from the reaction of the corresponding aromatic acyl chloride precursors with luminol. It has been found that depending on the size of aromatic groups, the formed luminol derivatives showed different properties, indicating distinct regulation of molecular skeletons. UV and IR data confirmed commonly the formation of imide group as well as aromatic segment in molecular structures. Thermal analysis showed that the thermal stability of luminol derivatives with p-phthaloyl segment was the highest in those derivatives. The difference of thermal stability is mainly attributed to the formation of imide group and aromatic substituent groups in molecular structure. The present results have demonstrated that the special properties of luminol derivatives can be turned by modifying molecular structures of objective compounds with proper substituted groups, which show potential application in functional material field and ECL sensor.

KARBON LİF ÜRETİMİNDE POLİAKRİLONİTRİL ELYAFLARIN TERMAL OKSİDASYONU

2021 ◽  
Vol 8 (17) ◽  
pp. 160-170
Author(s):  
Mahbubor Rahman ◽  
Tuba DEMIREL ◽  
Ismail KARACAN
Keyword(s):  
Thermal Stability ◽  
Aqueous Solution ◽  
Thermal Oxidation ◽  
Oxidation Process ◽  
Ammonium Persulfate ◽  
Oxidation Reactions ◽  
Carbon Yield ◽  
Thermal Stability Of ◽  
Pan Fibers

Thermal oxidation of polyacrylonitrile (PAN) fibers was accomplished at temperatures up to 250°C for different oxidation times. Chemical integration of PAN fibers with an aqueous solution of ammonium persulfate was performed before starting thermal oxidation. The results recommend that ammonium persulfate integration enhanced the oxidation reactions of the PAN fibers and resulting in enhanced thermal stability. Ammonium persulfate impregnation followed by the oxidation process in the air environment leads to significant deviations in the characteristics of PAN fibers. To perform structural characterization of the raw and ammonium persulfate (APS) incorporated and stabilized samples, XRD, IR-spectroscopy, TGA was executed in this study. Investigation of the XRD and infrared spectroscopy outcomes recommended quick aromatization reactions with growing oxidation periods. The TGA traces indicated a comparative enhancement in the thermal stability of the PAN fibers by the increased carbon yield with the rise of the oxidation time. The overall findings recommend that ammonium persulfate incorporation was very influential in stimulating the oxidation process.

Preparation and characterization of phase-change energy storage nonwoven fabric

2021 ◽  
pp. 152808372110417
Author(s):  
Zhou Zhao ◽  
Ningning Tong ◽  
Hong Song ◽  
Yan Guo ◽  
Jinmei Wang
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Energy Storage ◽  
Phase Change ◽  
Nonwoven Fabric ◽  
Scanning Calorimetry ◽  
Change Material ◽  
Stretching Process ◽  
Thermal Stability Of

In this work, a phase-change energy storage nonwoven fabric was made of polyurethane phase-change material (PUPCM) by a non-woven melt-blown machine. Polyethylene glycol 2000 was used as the phase transition unit and diphenyl-methane-diisocyanate as the hard segment to prepare PUPCM. Thermal stability of the PUPCM was evaluated through thermal stability analysis. The performance of pristine PUPCM was determined by Fourier transform infrared spectroscopy and differential scanning calorimetry to analyze the spinning technology of spinning temperature and the stretching process. Phase-change energy storage nonwoven fabric (413.22 g/m2) was prepared, and the morphology, solid–solid exothermic phase transition, mechanical properties, and the structures were characterized. The enthalpy of solid–solid exothermic phase transition reached 60.17 mJ/mg (peaked at 23.14°C). The enthalpy of solid–solid endothermic phase transition reached 67.09 mJ/mg (peaked at 34.34°C). The strength and elongation of phase-change energy storage nonwoven fabric were found suitable for garments and tent fabrics.

Biochemical Discrimination of Hurler and Scheie Syndromes

1979 ◽  
Vol 57 (3) ◽  
pp. 265-272 ◽  
Author(s):  
J. J. Hopwood ◽  
Vivienne Muller
Keyword(s):  
Thermal Stability ◽  
Skin Fibroblasts ◽  
Ph Optimum ◽  
Biochemical Evidence ◽  
Cultured Skin ◽  
Thermal Stability Of ◽  
Normal Controls

1. Homogenates of cultured skin fibroblasts derived from patients with α-l-iduronidase-deficiency disorders (Hurler and Scheie syndromes) were capable of hydrolysing iduronosyl anhydro-[l-3H]mannitol 6-sulphate although at considerably reduced rates compared with normal controls. 2. The Vmax. values of α-l-iduronidase from patients with Hurler or Scheie syndromes and from normal controls were 11, 12 and 833 pmol min−1 mg−1 of protein respectively; the corresponding apparent Km values were 656, 50 and 53 μmol/l respectively. The α-l-iduronidases from normal and Scheie fibroblast homogenates were shown to exhibit pH optima at 3·6 and 4·1 and were competitively inhibited by both chloride and sulphate ions: Hurler α-l-iduronidase activity exhibited one pH optimum at 3·8 and was also inhibited by chloride and to a lesser extent by sulphate ions. 3. The thermal stability of Hurler, Scheie and normal α-l-iduronidase activities at 55°C gave half-lives of approximately 1·0, 2·5 and 1·0 h respectively. 4. These biochemical findings clearly demonstrate enzyme differences for these two clinically distinct phenotypes and provide biochemical evidence that the Hurler and Scheie syndromes result from different allelic mutations.

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