you work for NextGenSugar Inc. who have generated several sugar analogs CHEM 377
ID: 205417 • Letter: Y
Question
you work for NextGenSugar Inc. who have generated several sugar analogs CHEM 377/641 Exam #1 NAME: 18)You work for NextGenSugar Inc., who have generated several sugar analogs but don't know anything about their metabolism. At your disposal are the radio-labeled sugar analogs, mammalian cells that grow in growth medium you can supplement with these analogs, and incubators that allow you to control oxygen. The first class of compounds you distinguish are those that can enter cells and those that cannot This is based on incubating cells with sugar analogs and seeing if the cells picked up radioactivity; no radioactivity meant that particular analog was not a substrate for GLUT1 transporter, or otherwise could not enter the cell. The following data are from experiments ONLY done with the sugar analogs that were picked up by cells After setting Ozlevelsto0%,in the incubator, you incubate the cells with media containing only individual sugar analogs alone. Of the 55 compounds tested 30 result in dead cells.0x Of these 30 compounds that caused cells to die in 0% 02, 1 did allow the production of much radio-labeled lactate per mol of glucose consumed. What enzyme was a metabolite of this sugar not a substrate for, and what radiolabeled glycolytic intermediate would these cells have high levels of? (A) dation as i lache dehydrocnay i Another analog allowed net ATP generation for a itle while, but then the cells died. They also failed to acidity their media, suggesting no lactate production. What enzyme was inhibited? You now test the 25 compounds that allowed survival without oxygen in a full oxygen environment. Surprisingly, 1 of these compounds now caused the cells to grow slowly and quickly acidify their media. What e (B) i does a metabolite of this analog inhibit? i When you grow cells with the radioactive version of this analog and unlabeled glucose you now notice all cell live and all TCA intermediates are radioactive. How did this happen?Explanation / Answer
Ans-
18. A)
The enzyme is lactate dehydrogenase (LDH). LDH catalyzes the conversion of lactate to pyruvic acid and back, as it converts NAD+ to NADH and back.
These cells would hace radiolabed pyruvic acid or pyruvate.
B) No lactate production means the action of enzyme - lactate dehydrogenase is inhibited.
because this LDH converts pyruave to lactate.
C) Production of lactic acid causes the media acidic
When glucose is not radio labeled but the TCA cycle intermediates are radio labeled. That means the pyruvate is radiolabaled and the action of pyruvate dehydrogenage produce acetyl-coA which goes to TCA cycle.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.