Protein Structure and Enzyme Activity

1985 ◽  
Vol 13 (6) ◽  
pp. 1253-1253
Author(s):  
A. R. TAMMAR
Keyword(s):  
Enzyme Activity ◽  
Protein Structure

The influence of putrescine on the structure, enzyme activity and stability of α-chymotrypsin

RSC Advances ◽  
2016 ◽  
Vol 6 (35) ◽  
pp. 29264-29278 ◽  
Author(s):  
Sadegh Farhadian ◽  
Behzad Shareghi ◽  
Ali A. Saboury ◽  
Mina Evini
Keyword(s):  
Enzyme Activity ◽  
Protein Structure ◽  
Protein Stability ◽  
Structure Activity

Information on protein stability is essential to study protein structure, activity, and interactions with ligands.

Surface modification mediates the interaction between fullerene and lysozyme: protein structure and antibacterial activity

2021 ◽  
Author(s):  
Yitong Bai ◽  
Xian Wu ◽  
Peng Ouyang ◽  
Mengyao Shi ◽  
Qun Li ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Enzyme Activity ◽  
Surface Modification ◽  
Protein Structure ◽  
Conformational Changes ◽  
Hydrophilic Surface ◽  
Protein Conformational Changes ◽  
Activity Loss

Hydrophilic surface modification enhanced the interaction between fullerene and lysozyme to induce more protein conformational changes and enzyme activity loss.

scholarly journals Contribution of Phe-7 to Tat-Dependent Export of β-Lactamase in Xanthomonas campestris

2012 ◽  
Vol 56 (7) ◽  
pp. 3597-3602 ◽  
Author(s):  
Chen-Wei Lee ◽  
Yi-Hsuan Tseng ◽  
Fu-Seng Deng ◽  
Juey-Wen Lin ◽  
Yi-Hsiung Tseng ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Protein Structure ◽  
Amino Acid ◽  
Xanthomonas Campestris ◽  
Constitutive Expression ◽  
Amino Acid Substitutions ◽  
Amino Acid Residues ◽  
Content Type ◽  
Aromatic Interactions ◽  
Tat Pathway

ABSTRACTStrains ofXanthomonas campestrispv. campestris isolated in Taiwan are commonly resistant to ampicillin owing to the constitutive expression of a chromosomally encoded β-lactamase that is secreted into the periplasm. In this study, we found that levels of β-lactamase vary amongX. campestrispv. campestris strains, a difference that can be attributed to amino acid substitutions at least at positions 7 and 206, with the former having the major impact. Bioinformatic and PCR analyses indicated thatX. campestrispv. campestris possessestatABCgenes and that the signal peptide ofX. campestrispv. campestris pre-Bla contains the typical twin-arginine motif (N-R-R-Q-F-L at amino acid residues 3 to 8 in strainX. campestrispv. campestris strain 11), suggesting that Bla is secreted via the Tat pathway. To assess the importance of Phe7in the efficient export ofX. campestrispv. campestris Bla, we prepared mutant constructs containing amino acid substitutions and monitored their expression by measuring enzyme activity and detecting Bla protein by Western blotting. The results indicate that replacement of Phe7with Leu severely inhibited Bla export whereas replacement with Pro almost abolished it. Although a change to Arg caused moderate inhibition of export, replacement with Tyr had no effect. These results suggest that for efficient export of Bla byX. campestrispv. campestris, the aromatic-aromatic interactions and stability of protein structure around the twin-arginine motif are important, since only proteins that can attain a folded state in the cytoplasm are competent for export via the Tat pathway.

Morphological and biochemical analyses of changes in rat hepatocytes related to wine and ethanol consumption

1984 ◽  
Vol 42 ◽  
pp. 232-233
Author(s):  
S.M. Geyer ◽  
C.L. Mendenhall ◽  
J.T. Hung ◽  
E.L. Cardell ◽  
R.L. Drake ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Enzyme Activity ◽  
Malic Enzyme ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Mature Male ◽  
Treatment Groups ◽  
Malic Enzyme Activity ◽  
Biochemical Analyses

Thirty-three mature male Holtzman rats were randomly placed in 3 treatment groups: Controls (C); Ethanolics (E); and Wine drinkers (W). The animals were fed synthetic diets (Lieber type) with ethanol or wine substituted isocalorically for carbohydrates in the diet of E and W groups, respectively. W received a volume of wine which provided the same gram quantity of alcohol consumed by E. The animals were sacrificed by decapitation after 6 weeks and the livers processed for quantitative triglycerides (T3), proteins, malic enzyme activity (MEA), light microscopy (LM) and electron microscopy (EM). Morphometric analysis of randomly selected LM and EM micrographs was performed to determine organellar changes in centrilobular (CV) and periportal (PV) regions of the liver. This analysis (Table 1) showed that hepatocytes from E were larger than those in C and W groups. Smooth endoplasmic reticulum decreased in E and increased in W compared to C values.

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