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Biomedical subjects

M Ray

Publications and source records attributed to M Ray.

At least 109 records · Page 6Linked to original sources

Uridine-diphosphate-glucose 4-epimerase from Saccharomyces fragilis. Inactivation by heat and reconstitution of the inactive enzyme.

UDP-glucose 4-epimerase from Saccharomyces fragilis is rapidly inactivated by heating at 42 degrees C for 7 min and at 45 degrees C for 4 min. The effector site, specific for sugar phosphates, is destroyed still earlier. The enzyme is inactivated by the dissocation of NAD from it leaving the dimeric structure unaffected. It can be reactivated by mercaptoethanol and NAD, both of which are essential for reactivation, and NAD becomes associated with the dimeric protein moiety.

Carbohydrate Epimerases

[Coronary artery spasm induced by the somministration of ergonovine maleate in subjects with spontaneous angina (author's transl)].

In 6 patients affected by spontaneous angina with S-T elevation and coronariographic findings of obstruction, intravenous administration of ergonovine maleate determined the same clinical and ECG patterns of spontaneous episodes. The coronary arteriography during pain showed a marked spasm with occlusion of a large coronary vessel in four patients. In 2 patients with atypical chest pain and normal coronariogram, E.M. did not induce pain, ECG abnormality or coronariographic alterations. The role of spasm in spontaneous angina is discussed.

Adult

The human complement after trypsin pretreatment as compared to the Paris standard.

A composite G-banding diagram after trypsin pretreatment of metaphase chromosomes from 5 different individuals (2 males and 3 females) is presented and compared with the Paris diagram. The patterns obtained by the present technique were very similar to those previously reported. It was found that the darkly staining bands were much more consistent in appearance than the lightly staining bands and that there was little individual variation.

Chromosomes

Galactose-6-phosphate dehydrogenase. Purification and partial characterization.

A new enzyme, galactose-6-phosphate dehydrogenase has been purified about 50-fold from goat liver. The enzyme can be distinguished from the nonspecific hexose-6-phosphate dehydrogenase and glucose-6-phosphate dehydrogenase by its high substrate specificity and absolute pyridine nucleotide requirement. In contrast to the hexose-6-phosphate dehydrogenase, this enzyme is located exclusively in the cytoplasmic fraction of the cell. The enzyme is a metalloprotein and is highly sensitive to mercurials. The product of the reaction is possibly a ketoaldose, phosphorylated at the primary alcoholic group.

Alcohol Oxidoreductases