Exam 1 Things Flashcards
Rate limiting enzyme in glycogenolysis
glycogen phosphorylase
Glycolysis occurs in
Cytosol
Calcium responsive element binding protein CREBP
Induces expression of insulin in the 2nd phase of release - the latest effect of insulin as GK increases
GLP-1 (glucagon like peptide 1)
An incretin; kinda to receptor on pancreatic beta cells and increases release of insulin
Why is soluble fiber good?
Forms a gel (making it functional fiber) which prevents reabsorprion of bile salts from the intestine/ return to the liver, lowering the serum LDL
GLUT2
Facilitated transporterdor brining monosaccharides into plasma down concentration gradient
Insulin synthesis
Comes from preproinsulin
Gets cleaves, C chain leaves. A and B held together by 2 thiols, thiol between chain A also
Insulin effect on K
Increases uptake of K via Na/K ATPase
Why does lactose intolerance lead to bad things?
Undigested lactose —> colon —> fermented to SCFA with gases —> water enters colon to reduce osmotic pressure —> diarrhea
glygogenin
in the absence of a preexisting glycogen polumer, will accept glucose from UDP-glucose
how does insulin relate to GSY?
insulin prevents GSY phosphorylation and increases dephosphorylation by activating protein phosphatase 1, and increasing GLUT4 membrane receptor levels
Enzyme that catalyses pyruvate to lactate
Lactate dehydrogenase
Insulin binding
Activates tyrosine kinase which phosphorylates intracellular proteins
Metabolic signal to GLUT4 and growth signal
Disaccharides are broken down (digested) by
Brush border enzymes located on microvilli of small intestine
ChREBP
Carbohydrate response element binding protein
Synergizes with SREBP1 for regulation of insulin gene expression
Phosphoglucase
Glucose-6-phosphate —> fructose-6-phosphate
phosophoglucomutase
glucose-6-P –> glucose-1-P
Glucagon binding
Binds to GPCR which activates cAMP which activates PKA (a ser/thr kinase)
what types of linkages does glycogen have?
alpha 1-4 and alpha 1-6
What effects does fiber have on the body?
- Hormonal effects
- Intrinsic effects
- Colonic effects
Decrease body weight
Pyruvate carboxylase
Pyruvate to OAA
What is the function of the Malate aspartate shuttle?
Get OAA out of the mitochondria to generate NAD outside the mito; gets converted into aspartate and then back to OAA then malate
where does glycogen synthesis occur?
mostly in the liver but also in the muscle
in the liver - prevents hypoglycemai
in the muscle - provides energy for muscle contraction
GLUT1
High in RBC/BVs
Glucose uptAke by skeletal muscle and fat
Glucagon
Made in alpha cells of pancreas
Stimulates synthesis and release of glucose *liver breaks down glycogen to release glucose into the blood
Stimulated by LOW blood glucose
glycogen synthase (GYS)
extends 10-20 glucose primer by alpha-1,4 glycosidic linkages
Na independent monosaccharide transport into enterocytes
Uses GLUT5 to bring fructose into the enterocyte thru facilitated diffusion
SGLT-1 (Na dependent) monosaccharide transport into enterocytes
Transports glucose/galactose and 2 Na ions- coupled to Ana/K ATPase to pump Na out of the cell and K in
Target genes of glucagon
PEPCK and glucose-6-phosphatase
Protein phosphatase 1
Activated by insulin to inhibit glucagon stimulation
PFK1
rate limiting enzyme of glycolysis!!!!
Fructose-6-p —> fructose-1,6-bisP
GLUT2 allows glucose to enter
Pancreatic beta cells
Hypokalemia
Sudden drop in plasma K due to too much insulin
SREBP1
Steroid response element binding protein 1
Insulin regulation of gene expression:
GK, PK, FA synthase, Glu-6-P dehydrogenase
2,3-bisphosphoglucerate BPG
Bound by Hb; lowers affinity for O2
More BPG means more O2 gets delivered to tissues (higher concentrations in higher altitude areas)
Insulin
Made in beta calls of pancreas
Inhibits synthesis and release of glucose
Induced by hyperglycemia
*liver cells take up glucose and store as glycogen
Rate limiting enzyme of glycolysis
Phosphofructokinase 1 (PFK1)
UDP glucose phosphorylase
glucsose 1-P –> UDP-glucose
malate dehydrogenase
malate –> OAA (generates NADH)
Polysaccharides are broken down in the mouth by
Alpha amylase
Epinephrine on metabolism
Stimulates glucose production and FA release
A heart attack usually has High elevated
LDH1 (LDHB)
branching enzyme
forms the branches in glycogen
Phases of glycolysis
Prep phase: uses 2 ATP
ATP gen. Phase: makes 4 ATP
PFK2
BFD because it has a kinase and phosphatase domain
Insulin is released in 2 waves
- 1st phase - preloaded vesicles
2. 2nd phase - after expression of insulin gene via Calcium responsive element binding protein CREBP
Insulin inhibition
Insulin binding —> PI3K and AKT activation —> FoXO phosphorylation —> exclusion from nucleus
In diabetes, liver is making lots of glucose and can’t get foxo out of nucleus
3 irreversible steps of gluconeogenesis
- Pyruvate —> PEP via OAA
- Dephosphorylation of fructose-1,6-bisphosphate by FBPase 1
- dephosphorylation of glucose-1-P by G6Pase
