Regulation of Calvin cycle Rubisco is a prime
Regulation of Calvin cycle Rubisco is a prime target for regulation
Activation of rubisco by carbamate
Rubisco is activated by carbamylation CO 2 concentration? p. H? Alkaline p. H favors Mg 2+ concentration?
conditions regulate stromal FBP-1 high light Stroma p. H And Mg 2+ Activation of Rubisco fig 20 -34
Redox regulation of Calvin cycle with Thioredox: Activation of enzymes by regulating redox states of a disulfide bond
redox regulation of Calvin cycle enzymes via thioredoxin high light fig 20 -36 Th-SH enz activity
Coordination of the light and dark reactions Light reactions Electron transfer Reduced ferrodoxin Thioredoxin Regulatory disulfide bonds in Calvin cycle enzymes Dark reactions
Coordination of the light and dark reactions Light reactions Electron transfer Reduced ferrodoxin p. H Mg 2+ Thioredoxin Regulatory disulfide bonds in Calvin cycle enzymes Dark reactions
Fat Metabolism
Americans are getting fatter, so do the people in other developed countries
Triacylglycerol: Fatty acids and glycerol Also called triglycerides or neutral fats Fatty acids
Various lipids
Dietary fats form micelles with the help of Bile salts
Lipases release fatty acids and monoacylglycerol
Transport lipids in Chylomicrons
from Mc. Donalds to Metabolism…
Summary of dietary lipids processing
Molecular structure of Chylomicrons
Mobilization of the stored Triacylglycerol in adipose tissue
Transport fatty acids from adipose tissue to muscle or other tissue Serum albumin
Fatty acids and glycerol are the products from lipase cleavage
Fate of glycerol
Physiological roles for fatty acids Building blocks for phosphalipis and glycolipids Covalent modification of proteins Fuel Precursor for hormones and signaling molecules
Fatty acids are oxidized in matrix of mitochondria Activation and transport fatty acids to mitochondria Three enzymatic reactions: Acyl Co. A synthetase Carnitine acyl transferase II
Activates fatty acid to form Acyl Co. A Driving by hydrolysis of pyrophosphate
Transport Fatty acids into mitochondria Carnitine acyltransferase II
Formation of Acyl carnitine
Normally, the transfer of an acyl group from an alcohol to sulfhyfryl group is thermodynamically unfavorable
Four basic steps in b-oxidation
Recurring metabolic motifs
Acyl-Co. A dehydrogenase: an enzyme similar to succinate dehydrogenase The enzyme is located on the inner membrane The product is always trans
Complex II succinate dehydrogenase Electron-transferring flavoprotein fig 19 -8
Enoyl-Co. A hydratase: similar to fumarase Always L configuration
B-hydroxyl-Co. A dehydrogenase: similar to malate dehydrogenase Only use L type of substrate
Thiolase
b-oxidation challenges monounsaturated FA polyunsaturated FA odd-carbon FA
An isomerase is needed for unsaturated
b-oxidation of polyunsaturated fatty acids fig 17 -10
b-oxidation of polyunsaturated fatty acids fig 17 -10
A reductase and an isomerase
Odd-chain fatty acids yield propionyl Co. A Propionyl Co. A carboxylase: biotin Mutase
the coenzyme B 12 reaction box 17 -2
Ketosis and ketone bodies
Synthesis of ketone bodies
Ketone bodies can be regarded as a watersoluble, transportable form of acetyl units, provide alternative fuels Ketone bodies are produced in liver and are a major source of energy for some tissues
From ketone bodies to acetyl Co. A
Unselfish liver
Diabetes and starvation leads to ketosis
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