Class Notes (835,730)
Canada (509,354)
BIOC13H3 (52)
Daman Bawa (12)
Lecture 4

Lecture 4.docx

8 Pages
103 Views
Unlock Document

Department
Biological Sciences
Course
BIOC13H3
Professor
Daman Bawa
Semester
Winter

Description
Key Concepts: The Pentose Phosphate Pathway  The pentose phosphate pathway takes place within the cytoplasm  Aka hexose monophosphate shunt or phosphogluconate pathway  Reduces two molecules of NADP to NADPH (nicotinamide adenine dinucleotide phosphate) for each glucose-6-phosphate that is oxidatively decarboxylated to ribulose-5-phosphate.  NADPH is functionally similar to NAD however, NADPH is the primary + reductant in the cell, whereas, NAD is the primary oxidant.  The PPP is also responsible for producing ribose-5-phosphate which provides the ribose sugar backbone that anchors the nucleotide base to DNA and RNA polymers Pentose Phosphate Pathway is critical for the cell  There are two main phases for PPP: o The oxidative phase generates NADPH which is required for many biosynthetic pathways and for detoxification of reactive oxygen species o The non-oxidative phase interconverts 3C, 4C, 5C, 6C and 7C monosaccharides to produce ribose-5-phosphate for nucleotide synthesis, and also to regenerate glucose-6-phosphate to maintain NADPH production by the oxidative phase. Net reaction:  Key Enzymes o Glucose-6-Phosphate Dehydrogenase (G6PD) - This is the first commited step in the pathway and is feedback-inhibited by NADPH. o Transketolase and Transaldolase - (converts ketose to aldose and aldose to ketose), together these two enzymes catalyze the reversible "carbon shuffle" reactions of the nonoxidative phase of the pathway  Pathways requiring NADPH include: o Synthesis  Fatty acid biosynthesis  Cholesterol biosynthesis  Neurotransmitter biosynthesis  Nucleotide biosynthesis o Detoxification  Reduction of oxidized glutathione (critical in RBC production)  Cytochrome P450 monooxygenases  Tissues with active PPPs. o Adrenal gland - steroid synthesis o Liver - fatty acid and cholesterol synthesis o Testes and Ovaries - steroid synthesis o Adipose tissue and Mammary gland - fatty acid synthesis o Red blood cells - maintenance of reduced glutathione Regulation of Pentose Phosphate Pathway  Glucose 6 Phosphate dehydrogenase is rate limiting  4 different metabolic scenarios govern how glycolysis and the pentose phosphate pathway are intertwined 1. Scenario where you need R5P in which you have a lot
More Less

Related notes for BIOC13H3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit