Purification and Properties of β- N -Acetylhexosaminidase from Mucor fragilis Grown in Bovine Blood

Abstract

Mucor fragilis grown on bovine blood powder as the sole carbon source abundantly produced P-Nacetylhexosaminidase. The enzyme activity was several times higher than that of a culture obtained with glucose medium. The enzyme had two different molecular weight forms. The high-molecular-weight form had somewhat higher ,B-N-acetylgalactosaminidase activity than the lower-molecular-weight enzyme which had 13-N-acetylgalactosaminidase activity equivalent to about 40 % of its ,B-N-acetylglucosaminidase activity. Bovine blood seemed to induce both enzymes, but N-acetylamino sugars specifically induced the low-molecular-weight form. N-Acetylgalactosamine had an especially marked effect on activity. The low-molecular-weight form of enzyme was purified from the culture filtrate by fractionation with ammonium sulfate and various column chromatographies. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The optimum pH was 4.0 to 5.0 for P-N-acetylglucosaminidase activity and 5.5 to 6.5 for P-Nacetylgalactosaminidase activity. The enzyme hydrolyzed natural substrates such as diN -acetylchitobiose, tri-N-acetylchitotriose, and a glycopeptide obtained by modification of fetuin.

Purification and characterization of thermostable beta-N-acetylhexosaminidase of Bacillus stearothermophilus CH-4 isolated from chitin-containing compost

“…The ,-HexNAcase isolated here had a high optimum temperature and good thermal stability compared with the enzymes from other mesophilic bacteria (25) and fungi (3,12,26,27); their optimum temperatures are around 45°C, while that of strain CH-4 is 75°C. The enzymes of other methophiles are inactivated completely at 55 to 65°C, while the enzyme of strain CH-4 is inactivated completely at 90°C.…”

“…showed specific characteristics compared with the enzymes from other sources (3,8,12,(25)(26)(27): the enzyme of strain CH-4 is a monomeric peptide, whereas many of the other enzymes are reportedly dimers. The ratio of the enzyme activities toward pNP-GalNAc and pNP-GlcNAc (0.26) was much lower than those of the enzymes from other sources, which are generally reported to be 1.2 to 1.5.…”

“…Chitooligosaccharides are usually prepared by partial hydrolysis of chitin with hydrochloric acid. They have also been prepared enzymatically by degradation (27) and transglycosylation (5). Enzymatic degradation of chitin appears to occur in two steps which are similar in procaryotes and eucaryotes.…”

Exploring Simplified Methods for Insect Chitin Extraction and Application as a Potential Alternative Bioethanol Resource

“…Mucor, a dimorphic Zygomycota, was found to produce bioethanol from various carbon sources like hydrolysates of lignocellulose [ 14 , 15 ]. Besides, some Mucor species were proved to produce chitin-degrading enzymes [ 16 , 17 ]. Following these reports pointed out strains of Mucor circinelloides able to produce bioethanol directly using chitin as a substrate in the submerged fermentation systems [ 8 ].…”

Purification and characterization of ββ‐N‐acetylhexosaminidase from the phytopathogenic fungusBipolaris sorokiniana

“…(Ueda and Arai 1992). Hexosaminidases from Aspergillus niger (Ball and Agrawal 1969), Mucor fragilis (Yamamoto et al 1986), Trichoderma harzanum ) and other fungi were also purified and characterized. In contrast to enzymes found in animal tissues, the presence of HEX isoenzymes is not unusual in microorganisms.…”