The anhydrofructose pathway of glycogen catabolism

Abstract

SummaryIn many living forms, glucose is stored in the polymeric form of glycogen and starch as a source of carbon and energy. Upon need, these polymers are broken down to their building block glucose in the presence of water and hydrolases, and glucose 1-phosphate in the presence of phosphate and phosphorylase. In the last decade, we established an alternative glycogen catabolic pathway, the so-called Anhydrofructose (AF) pathway, the description of which was approved by IUBMB in 2006. It is a pathway on the formation of an array of secondary metabolites from glycogen via the central intermediate 1,5-anhydro-Dfructose (AF). Furthermore, we demonstrated the occurrence of this pathway in both eukaryota and prokaryota. Metabolites of this pathway have been identified in mammals including humans. In this review, the physiological and molecular functions of these metabolites in the AF pathway as well as its regulation are discussed. IUBMBIUBMB Life, 60(12): 798-809, 2008

Molecular Basis for the Recognition of Long-chain Substrates by Plant α-Glucosidases

“…In GH31 enzymes, Cellvibrio japonicas ␣-xylosidase has an extra PA14 domain in the N-terminal part of the enzyme to accommodate long xylo-oligosaccharides (28). Gracilariopsis lemaneiformis ␣-1,4-glucan lyase (Protein Data Bank code 2X2I) possesses a second substrate-binding site in the N-terminal domain (29). However, neither the extra domain nor the surface binding site is found in the crystal structure of SBG.…”

Crystal Structure of α-1,4-Glucan Lyase, a Unique Glycoside Hydrolase Family Member with a Novel Catalytic Mechanism

“…Also, the possible existence of a separate base B Ϫ in the active site (9) or a water molecule activated Asp 665 (47) has been suggested. The acid catalyst Asp 665 is positioned on the opposite side of the ring and consequently cannot abstract the proton from C2, nor is there a suitable water molecule situated.…”

The Structure of Sucrose Synthase-1 from Arabidopsis thaliana and Its Functional Implications

“…Two model compounds were chosen that mimic the oxocarbenium-phosphate ion pair intermediate predicted by the S N i-like catalytic mechanism (Fig. 6): 1,5-anhydrofructose (NHF), which is a natural product (52), and lichenan (LCN), a tautomer of NHF that is a C2 deprotonation product of the D-glucopyranosylium (oxocarbenium ion) and contains a C1-C2 double bond. The primary difference between NHF and LCN is the extent of the planar portion of the ring, i.e.…”