Identification and characterization of D-xylulokinase from the D-xylose-fermenting fungus, Mucor circinelloides.
FEMS Microbiol Lett
; 360(1): 51-61, 2014 Nov.
Article
in En
| MEDLINE
| ID: mdl-25163569
ABSTRACT
D-Xylulokinase catalyzes the phosphorylation of D-xylulose in the final step of the pentose catabolic pathway to form d-xylulose-5-phosphate. The D-xylulokinase activity was found to be induced by both D-xylose and L-arabinose, as well as some of the other enzymes involved in the pentose catabolism, in the D-xylose-fermenting zygomycetous fungus, Mucor circinelloides NBRC 4572. The putative gene, xyl3, which may encode D-xylulokinase, was detected in the genome sequence of this strain. The amino acid sequence deduced from the gene was more similar to D-xylulokinases from an animal origin than from other fungi. The recombinant enzyme was purified from the E. coli transformant expressing xyl3 and then characterized. The ATP-dependent phosphorylative activity of the enzyme was the highest toward D-xylulose. Its kinetic parameters were determined as Km (D-xylulose) = 0.29 mM and Km (ATP) = 0.51 mM, indicating that the xyl3 gene encoded D-xylulokinase (McXK). Western blot analysis revealed that McXK was induced by L-arabinose as well as D-xylose and the induction was repressed in the presence of D-glucose, suggesting that the enzyme may be involved in the catabolism of D-xylose and L-arabinose and is subject to carbon catabolite repression in this fungus. This is the first study on D-xylulokinase from zygomycetous fungi.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Xylose
/
Recombinant Proteins
/
Phosphotransferases (Alcohol Group Acceptor)
/
Mucor
Type of study:
Diagnostic_studies
Language:
En
Journal:
FEMS Microbiol Lett
Year:
2014
Document type:
Article
Affiliation country: