Glucose Dehydrogenase

Strecker, Harold J.; Korkes, Seymour

doi:10.1016/s0021-9258(19)52408-5

Cited by 167 publications

(6 citation statements)

References 31 publications

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“…Based on stereoelectronic considerations, the anomer specificity of aldose oxidoreductases has been predicted (29). Assuming that hydride removal from the C 1 -atom of an aldopyranose takes place, the theory predicts that an optimally efficient catalyst should have an absolute specificity for the β-anomer of glucose, as is the case for NADdependent glucose dehydrogenase (30) and glucose oxidase (31). Since it appears now that sGDH is no exception to this rule, the question can be posed whether the aforementioned assumption also applies to this enzyme.…”

Section: Discussionmentioning

confidence: 99%

On the Mechanism and Specificity of Soluble, Quinoprotein Glucose Dehydrogenase in the Oxidation of Aldose Sugars

Olsthoorn

Duine

1998

Biochemistry

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Kinetic and optical studies were performed on the reductive half-reaction of soluble, quinoprotein glucose dehydrogenase (sGDH), i.e., on the conversion of sGDHox plus aldose sugar into sGDHred plus corresponding aldonolactone. It appears that the nature and stereochemical configuration of the substituents at certain positions in the aldose molecule determine the substrate specificity pattern: absolute specificity exists with respect to the C1-position (only sugars being oxidized which have the same configuration of the H/OH substituents at this site as the beta-anomer of glucose, not those with the opposite one) and with respect to the overall conformation of the sugar molecule (sugars with a 4C1 chair conformation are substrates, those with a 1C4 one are not); the nature and configuration of the substituents at the 3-position are hardly relevant for activity, and an equatorial pyranose group at the 4-position exhibits only aspecific hindering of the binding of the aldose moiety of a disaccharide. The pH optimum determined for glucose oxidation appeared to be 7.0, implying that reoxidation of sGDHred is rate-limiting with those electron acceptors displaying a different value under steady-state conditions. The kinetic mechanism of sGDH consists of (a) step(s) in which a fluorescing intermediate is formed, and a subsequent, irreversible step, determining the overall rate of the reductive half-reaction. The consequences of this for the likeliness of chemical mechanisms where glucose is oxidized by covalent catalysis in which a C5-adduct of glucose and PQQ are involved, or by hydride transfer from glucose to PQQ, followed by tautomerization of C5-reduced PQQ to PQQH2, are discussed. The negative cooperative behavior of sGDH seems to be due to substrate-occupation-dependent subunit interaction in the dimeric enzyme molecule, leading to a large increase of the turnover rate under saturating conditions.

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Section: Discussionmentioning

confidence: 99%

On the Mechanism and Specificity of Soluble, Quinoprotein Glucose Dehydrogenase in the Oxidation of Aldose Sugars

Olsthoorn

Duine

1998

Biochemistry

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“…Soskin et al (1938) showed that livers of dogs release glucose at low blood levels 1 During the course of these studies an alternate route of glucose phosphorylation in rat liver, possibly accounting for the high dependence on glucose concentration, was considered. This involves the direct oxidation of glucose, via glucose dehydrogenase (Harrison, 1931; Strecker and Korkes, 1952), followed by the successive actions of gluconokinase (Leder, 1957) and glucose-6-P dehydrogenase acting in reverse to yield glucose-6-P. However, two observations clearly ruled out this pathway as a quantitatively important one for glucose utilization in rat liver.…”

Section: Discussionmentioning

confidence: 99%

“…However, two observations clearly ruled out this pathway as a quantitatively important one for glucose utilization in rat liver. First, glucose dehydrogenase, when assayed by the method of Strecker and Korkes (1952) was not found in appreciable amounts in rat liver; second, "trapping" experiments were conducted in liver homogenates in which glucose-C14 and unlabeled gluconate were incubated together, and the remaining gluconate was isolated by adsorption and elution on an ion-exchange column. The resultant gluconate had only traces of radioactivity.…”

Section: Discussionmentioning

confidence: 99%

Studies on Glucose Phosphorylation in Rat Liver^*

DiPietro¹,

Sharma²,

Weinhouse³

1962

Biochemistry

196

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STUDIES ON GLUCOSE PHOSPHORYLATION IN RAT LIVER 455 activities found earlier (Greenberg and Glick, 1960 a), after administration of ACTH, are consistent with the requirement of the hypothesis of Haynes and Berthet (1957) that TPNH generation be increased via the G-6-P dehydrogenase reaction, and that the source of G-6-P be G-l-P derived from glycogen. An increase in phosphorylase activity leading to production of G-l-P would also be expected, and this has been borne out by subsequent studies to be reported later.

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“…Although the high Km values for glucose make a physiological role for glucose dehydrogenase activities somewhat suspect, the rather wide distribution of such activities in nature (see, for example, Metzger et al, 1964Metzger et al, , 1965; Strecker and Korkes, 1952;Imai et al, 1961;Hauge, 1966;King, 1966;Sadoff, 1966) suggests that they may have some significant metabolic function. Consistent with this idea is certain evidence in the literature, along with our observations on the activating effects of bicarbonate and other anions which are described in this paper.…”

Section: Discussionmentioning

confidence: 99%