Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A histochemical analysis of reaction rates of a series of enzymes was performed in electromotor neurons of the weakly electric fish Apteronotus leptorhynchus. These neurons were selected because of their functional homogeneity. The high metabolic activity of these cells as well as their large size facilitate cytophotometric analysis in cryostat sections. Sections were incubated for the activity of hexokinase, glucose-6-phosphate dehydrogenase, succinate dehydrogenase, NADPH dehydrogenase, NADPH ferrihaemoprotein reductase and beta-hydroxybutyrate dehydrogenase. All media contained polyvinyl alcohol as tissue stabilizer and Nitro BT as final electron acceptor. Measurements were performed with a Vickers M85a cytophotometer. Linear relationships between the specific formation of formazan (test minus control reaction) and incubation time were obtained for all enzymes although some reactions showed an initial lag phase or an intercept with the ordinate. The relatively high activities of hexokinase, succinate dehydrogenase and the extremely low activity of hydroxybutyrate dehydrogenase indicate that energy is mainly supplied by glycolysis. Glucose-6-phosphate dehydrogenase showed a high activity whereas NADPH reductase and dehydrogenase activity were low in electromotor neurons, indicating that the NADPH generated is largely used for biosynthesis. Despite their synchronous firing pattern activity, electromotor neurons showed a considerable heterogeneity with respect to their metabolic activity.
 ...
PMID:Enzyme reaction rate studies in electromotor neurons of the weakly electric fish Apteronotus leptorhynchus. 251 71

The effect of endogenous 6-phosphogluconate dehydrogenase (6PGDH) on the histochemical quantification of low-Km hexokinase activity in rat submandibular salivary glands has been investigated using a Seescan Solitaire Plus image analysis system and a modified black and white Newvicon TV camera. Absorbance readings of neutral density filters were close to their known absorbance values. A significant correlation was found between the absorbance of Nitro BT reduction products within sections, with and without the use of a 588 nm interference filter. Furthermore, absorbance readings obtained from 8 microns-thick sections were 1.92 and 2.22 times greater than values obtained from 4 microns-thick sections using 'white' and 588 nm light respectively. The level of background illumination was not critical for absorbance measurements provided it was below the level that saturated the Newvicon camera and was not changed between background and image capture. The greatest variations in absorbance readings on tissue sections were associated with changes in zoom and objective combinations. Our studies indicate that this relatively low cost image analysis system can give reproducible absorbance readings from various structures defined in digitized, captured images of tissue sections. Results from continuous monitoring studies indicated that the high levels of 6PGDH activity in excretory ducts caused a 1.67-fold overestimation of hexokinase activity as assessed by absorbance readings performed throughout a 22-minute reaction period. By contrast, overestimation of hexokinase activity in salivary gland acini only became apparent after 8 min incubation with a 1.4-fold overestimation being seen at 22 min. This difference appears to reflect the relatively low hexokinase and 6PGDH activities present in acini compared with excretory ducts.
 ...
PMID:The use of continuous monitoring and computer-assisted image analysis for the histochemical quantification of hexokinase activity. 259 49