An endo-alpha1 leads to 6-D-mannanase from a soil bacterium. Purification, properties, and mode of action.
A soil organism, isolated by enrichment culture on unbranched alpha1 leads to 6-mannan backbone from the yeast Saccharomyces cerevisiae, secretes and endo-alpha1 leads to 6-mannanase. We have purified this mannanase to homogeneity and find it to consist of a single polypeptide chain with a molecular weight of about 131,000. The enzyme is unusually heat-stable and appears to be highly extended in shape, possessing very little alpha helicity but with a high proportion of beta structure. The mannanase acts on unbranched alpha1 leads to 6-mannan to produce mannose and alpha1 leads to 6-mannobiose, with the intermediate formation of alpha1 leads to 6-mannooligosaccharides of various sizes. Calcium ion is required for full activity. The smallest substrate is the alpha1 leads to 6-mannotriose, whereas the reduced mannotriose is an inhibitor. The combining site appears to encompass 6 to 8 mannose units.
D000596:Amino Acids / Q000032:analysis; D001419:Bacteria / Q000201:enzymology*; D002413:Cations, Divalent; D002942:Circular Dichroism; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism; D008970:Molecular Weight; D009844:Oligosaccharides; D011134:Polysaccharides / Q000378:metabolism; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae; D012988:Soil Microbiology; D013329:Structure-Activity Relationship; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D000596:Amino Acids; D002413:Cations, Divalent; D009844:Oligosaccharides; D011134:Polysaccharides; D013439:Sulfhydryl Reagents; D004492:Edetic Acid; D006026:Glycoside Hydrolases; D008358:Mannose