The Reaction of Amylases with Starch Granules<sup>1,2</sup>

Nordin, P.; Kim, So Hyun

doi:10.1021/ja01502a040

Cited by 15 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The manner in which many rumen amylases act in vivo may be through their action on raw starch granules. A number of researchers (1,14,19,26,27,34,35) have demonstrated the action of various amylases on different types of starch granules. The enzyme ofB.…”

Section: Gi' 0 5 'mentioning

confidence: 99%

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

McWethy¹,

Hartman²

1977

J Bacteriol

View full text Add to dashboard Cite

A medium was developed to obtain maximum yields of extracellular amylase from Bacteroides amylophilus 70. Crude enzyme preparations, obtained by ammonium sulfate precipitation of cell-free broth, contained six amylolytic isoenzymes that were detected by isoelectric focusing and polyacrylamide gel electrophoresis. One of these amylases was purified by diethylaminoethyl-Sephadex A-50 ion-exchange chromatography and Sephadex G-200 gel filtration techniques. Some properties of the purified extracellular a-amylase were: optimum pH, 6.3; optimum temperature, 43°C; pH stability range, 5.8 to 7.5; isoelectric point, pH 4.6; molecular weight, 92,000 (by sodium dodecyl sulfatedisc gel electrophoresis); and sugars causing inhibition, cyclomaltoheptaose, cyclomaltohexaose, and aD -phenylglucoside. In addition, Ca2+ and Co2+ were strong activators, and Hg2+ was a strong inhibitor; all other cations were slightly stimulatory. Dialysis against 0.01 M ethylenediaminetetraacetic acid caused a 58% loss of activity that was restored to 92% of the original by the addition of 0.04 M Ca2+. The enzyme affected a blue-value-reducing-value curve characteristic of alpha-type amylases. The relative rates of hydrolysis of amylose, soluble starch, amylopectin, and dextrin were 100, 97, 92, and 60%, respectively; Michaelis constants for these substrates were 18.2, 18.7, 18.2, and 16.7 ,umol of D-glucosidic bond/liter, respectively. The enzyme degraded maize (corn) starch granules to some extent and had relatively little activity on potato starch granules. Digestion of starch in the rumen is essential to maximum utilization of feed grains by the ruminant. To gain an understanding of starch digestion in the rumen, attempts have been made to purify and characterize rumen amylases. At present, however, only three rumen amylases, produced by Streptococcus bovis (10, 33, 35), Clostridium butyricum (10, 35), and Bacteroides amylophilus (S. S. Rahman, Ph.D. thesis, University of British Columbia, Vancouver, 1970, Diss. Abstr. 32:77), have been partially characterized. B. amylophilus produces extracellular amylases and may play an important role as a starch digester in the rumen (9). This report presents data on the production, purification, and characterization of this amylase and defines its possible role in rumen starch breakdown. MATERIALS AND METHODS Organism and cultural conditions. The organism used in this study was B. amylophilus 70, kindly ' Joumal paper no. J-8471 of the Iowa Agriculture and

show abstract

Section: Gi' 0 5 'mentioning

confidence: 99%

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

McWethy¹,

Hartman²

1977

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…These studies have involved x-ray diffraction patterns (41,42), preferential hydrolysis by acids (43), and degradation by en zymes (44). However, very little is actually known about how the components of the granule are held together and the nature of their association.…”

Section: Bacillus Polymyxamentioning

confidence: 99%

Action patterns of some alpha-type amylases

Robyt

View full text Add to dashboard Cite

Α-1,4-Glucans. PART XX. THE MOLECULAR STRUCTURE OF THE STARCHES FROM OATS AND MALTED OATS*

Manners

Bathgate

1969

Journal of the Institute of Brewing

View full text Add to dashboard Cite

Starch was isolated from samples of oats and malted oats, and fractionated into amylose and amylopectin components. Analysis showed that malting caused a very limited decrease in the molecular size of the amylose, and a small but significant reduction in the exterior chain length of the amylopectin. These changes are very similar to those which occur when oat starch granules are subjected to limited α‐amylolysis. It is suggested that α‐amylase is the predominant enzyme involved in the changes which occur in cereal starches during malting.

show abstract

The Reaction of Amylases with Starch Granules^1,2

Cited by 15 publications

References 3 publications

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

Action patterns of some alpha-type amylases

Α-1,4-Glucans. PART XX. THE MOLECULAR STRUCTURE OF THE STARCHES FROM OATS AND MALTED OATS*

Contact Info

Product

Resources

About

The Reaction of Amylases with Starch Granules1,2

Cited by 15 publications

References 3 publications

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus

Action patterns of some alpha-type amylases

Α-1,4-Glucans. PART XX. THE MOLECULAR STRUCTURE OF THE STARCHES FROM OATS AND MALTED OATS*

Contact Info

Product

Resources

About

The Reaction of Amylases with Starch Granules^1,2