Biomaterial Database

Side chain reactivities of glucoamylase G2 from Aspergillus niger evaluated by group-specific chemical modifications. 1989

K Håkansson, and B Svensson

Department of Chemistry, Carlsberg Laboratory, Copenhagen Valby.

Treatment of glucoamylase G2 with large excesses of different group specific reagents resulted in modification of 25% of the histidyl, 15% of the tyrosyl, 20-40% of the arginyl, 30-50% of the lysyl and none of the methionyl residues. The modified groups were not critical since the various derivatives possessed from 50% to 100% residual enzymatic activity and retained the thermostability. Carboxamidomethylation occurred specifically at His254 with essentially no change of the kinetic parameters for hydrolysis of maltose and starch. Removal of the two N-linked sugar units by endoglycosidase H was similarly without effect on activity, thermostability and chemical reactivity of the histidyl residues. H(+)-titration revealed that glucoamylase G2 carries a lower net charge throughout the pH-range 3-11 than predicted from its amino acid composition.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D008320	Maltose	A dextrodisaccharide from malt and starch. It is used as a sweetening agent and fermentable intermediate in brewing. (Grant & Hackh's Chemical Dictionary, 5th ed)
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D005087	Glucan 1,4-alpha-Glucosidase	An enzyme that catalyzes the hydrolysis of terminal 1,4-linked alpha-D-glucose residues successively from non-reducing ends of polysaccharide chains with the release of beta-glucose. It is also able to hydrolyze 1,6-alpha-glucosidic bonds when the next bond in sequence is 1,4.	1,4-alpha-Glucosidase, Exo,Amyloglucosidase,Exo-1,4-alpha-Glucosidase,Glucoamylase,gamma-Amylase,Glucoamylase G1,Glucoamylase G2,1,4-alpha-Glucosidase, Glucan,Exo 1,4 alpha Glucosidase,Glucan 1,4 alpha Glucosidase,gamma Amylase
D006639	Histidine	An essential amino acid that is required for the production of HISTAMINE.	Histidine, L-isomer,L-Histidine,Histidine, L isomer,L-isomer Histidine
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000118	Acetylglucosaminidase	A beta-N-Acetylhexosaminidase that catalyzes the hydrolysis of terminal, non-reducing 2-acetamido-2-deoxy-beta-glucose residues in chitobiose and higher analogs as well as in glycoproteins. Has been used widely in structural studies on bacterial cell walls and in the study of diseases such as MUCOLIPIDOSIS and various inflammatory disorders of muscle and connective tissue.	N-Acetyl-beta-D-glucosaminidase,Chitobiase,N,N-Diacetylchitobiase,N-Ac-beta-Glucosaminidase,NAGase,beta-D-Acetamido-2-Deoxyglucosidase,beta-D-N-acetylglucosaminidase,beta-N-Acetylglucosaminidase,N Ac beta Glucosaminidase,N Acetyl beta D glucosaminidase,N,N Diacetylchitobiase,beta D Acetamido 2 Deoxyglucosidase,beta D N acetylglucosaminidase,beta N Acetylglucosaminidase
D001120	Arginine	An essential amino acid that is physiologically active in the L-form.	Arginine Hydrochloride,Arginine, L-Isomer,DL-Arginine Acetate, Monohydrate,L-Arginine,Arginine, L Isomer,DL Arginine Acetate, Monohydrate,Hydrochloride, Arginine,L Arginine,L-Isomer Arginine,Monohydrate DL-Arginine Acetate