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Journal ArticleDOI

Studies on pH and thermal deactivation of pectolytic enzymes from Aspergillus niger

01 Oct 2003-Biochemical Engineering Journal (Elsevier)-Vol. 16, Iss: 1, pp 57-67
TL;DR: The addition of protein doubled the half-life times of partially purified PMG, PG I and PG II and the interaction effect of pectolytic enzymes on deactivation was found to be significant.
About: This article is published in Biochemical Engineering Journal.The article was published on 2003-10-01. It has received 108 citations till now.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the enzyme was characterized with respect to its activity and stability at various pH and temperature ranges using SDS-PAGE profiling, which revealed that the enzyme had two bands with the molecular weights of 36 and 53 kDa.

67 citations

Journal ArticleDOI
TL;DR: In this paper, pyromellitic anhydride acid and poly(maleic anhydrides) were used for chemical modification of lysine residues in stem bromelain.
Abstract: Chemical modification of lysine residues in stem bromelain was carried out using two novel reagents pyromellitic anhydride acid and poly(maleic anhydride). About 60% and 57% of the residues in bromelain were found to be modified by pyromellitic anhydride and poly(maleic anhydride), respectively. The modification brought about enhancement of thermal stability and the resistance to alkali and the surfactant. The optimum pH shifted from 7 to 9. Thermodynamic parameters, Δ H *, Δ G * and Δ S *, were determined as a function of temperature. The kinetic constants K m of the modified enzymes were determined as 0.4092 × 10 −2 and 0.2825 × 10 −2 mol l −1 , respectively. SDS-PAGE profiling revealed a major bands of native and modified enzyme with molecular weights of 26 and 28.5 kDa. The results of FT-IR studies suggested that the modification caused only local structural changes. These results provide guidance for future development of stable protein formulations.

66 citations

Journal ArticleDOI
TL;DR: β-Galactosidases produced by pure and mixed cultures of Streptococcus thermophilus 95/2 and Lactobacillus delbrueckii ssp bulgaricus 77 (Lb 77) isolated from the Toros mountain region of Turkey were characterised with respect to their biochemical and thermal properties and could be considered as potential candidates for lactose hydrolysis of milk and milk products.

61 citations


Cites background from "Studies on pH and thermal deactivat..."

  • ...Numerical values of DH* and DS* are highly influenced by various factors, including the solvent and structural effects (Naidu & Panda, 2003)....

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  • ...Inactivation is known to be a process where the secondary, tertiary or quaternary structure of a protein changes without breaking covalent bonds (Naidu & Panda, 2003)....

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Journal ArticleDOI
TL;DR: In this article, a crude exo-polygalacturonase enzyme (produced by Aspergillus sojae) was characterized with respect to its biochemical and thermal properties.

60 citations

Journal ArticleDOI
TL;DR: Inhibition kinetic showed that enzyme is serine protease because enzyme was competitively inhibited by antipain and aprotinin as these compounds are known to be competitive inhibitors of serine proline protease.

59 citations

References
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Journal Article
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.

289,852 citations

Journal ArticleDOI
TL;DR: In this paper, the probability of the activated state is calculated using ordinary statistical mechanics, and the probability multiplied by the rate of decomposition gives the specific rate of reaction, and necessary conditions for general statistical treatment to reduce to the usual kinetic treatment are given.
Abstract: The calculation of absolute reaction rates is formulated in terms of quantities which are available from the potential surfaces which can be constructed at the present time. The probability of the activated state is calculated using ordinary statistical mechanics. This probability multiplied by the rate of decomposition gives the specific rate of reaction. The occurrence of quantized vibrations in the activated complex, in degrees of freedom which are unquantized in the original molecules, leads to relative reaction rates for isotopes quite different from the rates predicted using simple kinetic theory. The necessary conditions for the general statistical treatment to reduce to the usual kinetic treatment are given.

4,718 citations

Book ChapterDOI

3,073 citations

Journal ArticleDOI
TL;DR: This review discusses various types of pectinases and their applications in the commercial sector.

1,001 citations