Acyl carrier protein (ACP) inhibition and other differences between β-ketoacyl synthase (KAS) I and II

2000 ◽  
Vol 28 (6) ◽  
pp. 607-610 ◽  
Author(s):  
K. Arnvig McGuire ◽  
J. N. McGuire ◽  
P. von Wettstein-Knowles
Keyword(s):  
Transfer Reaction ◽  
Acyl Carrier Protein ◽  
Laser Desorption ◽  
Acid Synthesis ◽  
Carrier Protein ◽  
Binding Affinities ◽  
Laser Desorption Ionization ◽  
Physiological Concentration ◽  
Ionization Time ◽  
Ketoacyl Synthase

Escherichia coli β-ketoacyl synthases (KAS) I and II carry out the elongation steps in fatty acid synthesis. Analyses using the cross-linker BSa [bis(sulphosuccinimidyl) suberate] and surfaceenhanced laser desorption/ionization-time-offlight MS disclosed only monomeric and dimeric forms of KAS II, whereas KAS I also forms higher multimers. The binding affinities for KAS I and KAS II to C14-acyl carrier protein (ACP) as well as for C14-ACP to KAS I and KAS II were determined. KAS I is sensitive to the ACP released during the transfer reaction, with 50% inhibition at 0.17 μM ACP close to the physiological concentration of ACP (0.13 μM). KAS I and II also differ in carrying out the decarboxylation step of the elongation reaction.

scholarly journals Identification of Adult Fasciola spp. Using Matrix-Assisted Laser/Desorption Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

2020 ◽  
Vol 9 (1) ◽  
pp. 82
Author(s):  
Issa Sy ◽  
Lena Margardt ◽  
Emmanuel O. Ngbede ◽  
Mohammed I. Adah ◽  
Saheed T. Yusuf ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Specific Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Species Specific ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Fascioliasis is a neglected trematode infection caused by Fasciola gigantica and Fasciola hepatica. Routine diagnosis of fascioliasis relies on macroscopic identification of adult worms in liver tissue of slaughtered animals, and microscopic detection of eggs in fecal samples of animals and humans. However, the diagnostic accuracy of morphological techniques and stool microscopy is low. Molecular diagnostics (e.g., polymerase chain reaction (PCR)) are more reliable, but these techniques are not routinely available in clinical microbiology laboratories. Matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a widely-used technique for identification of bacteria and fungi; yet, standardized protocols and databases for parasite detection need to be developed. The purpose of this study was to develop and validate an in-house database for Fasciola species-specific identification. To achieve this goal, the posterior parts of seven adult F. gigantica and one adult F. hepatica were processed and subjected to MALDI-TOF MS to create main spectra profiles (MSPs). Repeatability and reproducibility tests were performed to develop the database. A principal component analysis revealed significant differences between the spectra of F. gigantica and F. hepatica. Subsequently, 78 Fasciola samples were analyzed by MALDI-TOF MS using the previously developed database, out of which 98.7% (n = 74) and 100% (n = 3) were correctly identified as F. gigantica and F. hepatica, respectively. Log score values ranged between 1.73 and 2.23, thus indicating a reliable identification. We conclude that MALDI-TOF MS can provide species-specific identification of medically relevant liver flukes.

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