Biotechnological potential of an exo‐polygalacturonase of the new strain
            Penicillium janthinellum
            VI2R3M: biochemical characterization and clarification of fruit juices

Methylation is a common structural modification that can alter and improve the biological activities of natural compounds. O-Methyltransferases (OMTs) catalyze the methylation of a wide array of secondary metabolites, including flavonoids, and are potentially useful tools for the biotechnological production of valuable natural products. An OMT gene (PfOMT3) was isolated from perilla leaves as a putative flavonoid OMT (FOMT). Phylogenetic analysis and sequence comparisons showed that PfOMT3 is a class II OMT. Recombinant PfOMT3 catalyzed the methylation of flavonoid substrates, whereas no methylated product was detected in PfOMT3 reactions with phenylpropanoid substrates. Structural analyses of the methylation products revealed that PfOMT3 regiospecifically transfers a methyl group to the 7-OH of flavonoids. These results indicate that PfOMT3 is an FOMT that catalyzes the 7-O-methylation of flavonoids. PfOMT3 methylated diverse flavonoids regardless of their backbone structure. Chrysin, naringenin and apigenin were found to be the preferred substrates of PfOMT3. Recombinant PfOMT3 showed moderate OMT activity toward eriodictyol, luteolin and kaempferol. To assess the biotechnological potential of PfOMT3, the biotransformation of flavonoids was performed using PfOMT3-transformed Escherichia coli. Naringenin and kaempferol were successfully bioconverted to the 7-methylated products sakuranetin and rhamnocitrin, respectively, by E. coli harboring PfOMT3.

Download Full-text

Xylanases of Cellulomonas flavigena: expression, biochemical characterization, and biotechnological potential

AMB Express ◽

10.1186/s13568-016-0308-7 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 6

Author(s):

Alexander V. Lisov ◽

Oksana V. Belova ◽

Zoya A. Lisova ◽

Nataliy G. Vinokurova ◽

Alexey S. Nagel ◽

...

Keyword(s):

Biochemical Characterization ◽

Biotechnological Potential ◽

Cellulomonas Flavigena

Download Full-text

Properties of a non collagen-degradingBacillus subtiliskeratinase

Canadian Journal of Microbiology ◽

10.1139/w07-124 ◽

2008 ◽

Vol 54 (3) ◽

pp. 180-188 ◽

Cited By ~ 18

Author(s):

Alexandre José Macedo ◽

Walter Orlando Beys da Silva ◽

Carlos Termignoni

Keyword(s):

Bacillus Subtilis ◽

Amino Acid ◽

Molecular Mass ◽

Biochemical Characterization ◽

Detectable Effect ◽

Amino Acid Residues ◽

Keratinolytic Activity ◽

Biotechnological Potential ◽

Optimum Ph

Bacillus subtilis S14 produces a keratinase (KerS14) with non collagen-degrading activity. Indeed, this is the first keratinase described so far that does not have any detectable effect on collagen, which is a crucial property for an enzyme intended to be used in skin dehairing. Because of its importance as an industrial tanning enzyme, we report the biochemical characterization of KerS14. This protein exhibited an apparent molecular mass of 27 kDa, a pI of 6.5, and an optimum pH in the range of 8.0–9.0. The enzyme’s activity was stimulated by Mn2+(7.7-fold), Ca2+(6.1-fold), Mg2+(4.9-fold), and Co2+(4.0-fold) but was inhibited by Cu2+and Zn2+. Using p-nitroanilide and methylcoumarine derivatized peptides, we observed that KerS14 prefered Arg at subsite P1, small amino acid residues at subsite P2, and Gln or Glu at subsite P3. KerS14 presented higher keratin degradation specificity than other commercial proteases. Its high keratinolytic activity and the absence of virtually any activity against collagen remark the biotechnological potential of this enzyme to be used at larger scales in tannery dehairing processes.

Download Full-text

Plant Pathology Diagnosed by X-Ray Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129152 ◽

1987 ◽

Vol 45 ◽

pp. 974-975

Author(s):

J. H. Resau ◽

N. Howell ◽

S. H. Chang

Keyword(s):

Electron Microscopy ◽

Plant Pathology ◽

Biochemical Characterization ◽

Nutrient Deficiency ◽

Green Leaf ◽

Parasitic Infestation ◽

X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

Download Full-text

The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146217 ◽

1993 ◽

Vol 51 ◽

pp. 74-75

Author(s):

Jason R. Swedlow ◽

Neil Osheroff ◽

Tim Karr ◽

John W. Sedat ◽

David A. Agard

Keyword(s):

Topoisomerase Ii ◽

Biochemical Characterization ◽

Developmental Cycle ◽

Dna Topoisomerase Ii ◽

Chromosomal Distribution ◽

Dna Topoisomerase ◽

Ideal System ◽

Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

Download Full-text