Abstract
A new facet of the specificity of the glycogen-debranching enzyme, isoamylase, namely, the hydrolysis of a carbohydrate-amino acid linkage, is described. This bond joins the terminal, reducing-end D-glucose unit of glycogen to the hydroxyl group of tyrosine in glycogenin, the primer protein for glycogen biogenesis. The specificity was further defined by demonstrating that 4-nitrophenyl α-maltotrioside and higher homologs also act as substrates. The splitting of the glycogen-glycogenin bond by isoamylase indicates the α-anomeric configuration of the terminal D-glucose unit. It also provides a means of preparing apoglycogenin. Pullulanase, a somewhat similar starch- and glycogen-debranching enzyme, does not split these new isoamylase substrates, permitting the 4-nitrophenyl saccharides to be used in distinguishing between isoamylase and pullulanase.
| Original language | English |
|---|---|
| Pages (from-to) | 331-338 |
| Number of pages | 8 |
| Journal | Carbohydrate Research |
| Volume | 227 |
| DOIs | |
| State | Published - Apr 6 1992 |
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ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Organic Chemistry
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The substrate specificity of isoamylase and the preparation of apo-glycogenin. / Lomako, J.; Lomako, W. M.; Whelan, William J.
In: Carbohydrate Research, Vol. 227, 06.04.1992, p. 331-338.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The substrate specificity of isoamylase and the preparation of apo-glycogenin
AU - Lomako, J.
AU - Lomako, W. M.
AU - Whelan, William J.
PY - 1992/4/6
Y1 - 1992/4/6
N2 - A new facet of the specificity of the glycogen-debranching enzyme, isoamylase, namely, the hydrolysis of a carbohydrate-amino acid linkage, is described. This bond joins the terminal, reducing-end D-glucose unit of glycogen to the hydroxyl group of tyrosine in glycogenin, the primer protein for glycogen biogenesis. The specificity was further defined by demonstrating that 4-nitrophenyl α-maltotrioside and higher homologs also act as substrates. The splitting of the glycogen-glycogenin bond by isoamylase indicates the α-anomeric configuration of the terminal D-glucose unit. It also provides a means of preparing apoglycogenin. Pullulanase, a somewhat similar starch- and glycogen-debranching enzyme, does not split these new isoamylase substrates, permitting the 4-nitrophenyl saccharides to be used in distinguishing between isoamylase and pullulanase.
AB - A new facet of the specificity of the glycogen-debranching enzyme, isoamylase, namely, the hydrolysis of a carbohydrate-amino acid linkage, is described. This bond joins the terminal, reducing-end D-glucose unit of glycogen to the hydroxyl group of tyrosine in glycogenin, the primer protein for glycogen biogenesis. The specificity was further defined by demonstrating that 4-nitrophenyl α-maltotrioside and higher homologs also act as substrates. The splitting of the glycogen-glycogenin bond by isoamylase indicates the α-anomeric configuration of the terminal D-glucose unit. It also provides a means of preparing apoglycogenin. Pullulanase, a somewhat similar starch- and glycogen-debranching enzyme, does not split these new isoamylase substrates, permitting the 4-nitrophenyl saccharides to be used in distinguishing between isoamylase and pullulanase.
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UR - http://www.scopus.com/inward/citedby.url?scp=0027113467&partnerID=8YFLogxK
U2 - 10.1016/0008-6215(92)85082-B
DO - 10.1016/0008-6215(92)85082-B
M3 - Article
C2 - 1499031
AN - SCOPUS:0027113467
VL - 227
SP - 331
EP - 338
JO - Carbohydrate Research
JF - Carbohydrate Research
SN - 0008-6215
ER -