Welcome to Trypanosome Metabolism!
A. Important Metabolic Processes
B. Metabolic Machinery

A. Important Metabolic Processes
dfdfdfddeWhile the metabolic workings of trypanosomes are complex and all factors are important, four main pathways are particularly relevant to the most recent findings. An overview of each of these four pathways are outlined below to provide a basic understanding of the importance of each in an organism's survival.

Glycolysis
fgfgfgfggfg Pentose Phosphate
fgggggggggggggggggggggg Citric Acid Cycle
gggggggggggggggggggggggggggggggg Lipid Biosynthesis

Glycolysis
ghg Glucose is a major fuel of most organisms and occupies a central position in metabolism. In higher eukaryotes, glucose has three major fates.
ghhhhhhhhhhh1. Glucose may be stored as glycogen, starch, and sucrose.
fffffffffffffffffffff2. Glucose can be oxidized to pyruvate via glycolysis.
fffffffffffffffffffff3. Glucose can be oxidized to pentoses via the pentose phosphate pathway.
gggggIn glycolysis, a molecule of glucose is degraded in a series of enzyme-catalyzed reactions to yield two molecules of the three-carbon compound pyruvate. During the reactions of glycolysis, free energy released is conserved in ATP and NADH (Nelson
and Cox, 527).

Pentose Phosphate Pathway
dfdfdGlucose has other catabolic fates besides glycolysis, serving the purpose of providing a cell with specialized products that it may need.
fgfgfgThe pentose phosphate pathway converts glucose-6-phosphate to:
fffffffffffff1. NADPH-Carrying energy in the form of reducing power.
fffffffffffff2. Ribose 5-phosphate-Necessary for the synthesis of nucleic acids.

Citric Acid Cycle
ddddThe citric acid is the second step of cellular respiration, following conversion of glucose to pyruvate by glycolysis depicted above. In this second stage, pyruvate is converted to acetyl-CoA which enters the citric acid cycle. The acetyl-CoA is oxidized to CO2 as the energy of oxidation is conserved in the reduced electron carriers NADH and FADH2.

Lipid Biosynthesis
dddddLipids are the principal form of stored energy and the constituents of cell membranes in most organisms. The ability to synthesize many types of lipids is essential to a cell's ability to produce energy, have all of its necessary vitamins, transport ions and molecules, and send intracellular messages.

B. Metabolic Machinery
1. Matching Organelles with Organisms
sdsddPeroxisomes of higher eukaryotes (animals), glyoxysomes of plants, and glycosomes of kinoplastids are related microbody organelles that perform specific metabolic functions tailored to their cellular environments (Parsons, 19). Eukaryotes only get of this type of organelle and plants only get one type…
dddddddddare kinoplastids intermediates? Oddballs?
dddddddddddddThe missing evolutionary link?
ffffffffffffffffffffffffffffffffffffffffRead on to find out more!

2. Apples to Oranges: Making Comparisons
dddddPeroxisomes, glyoxysomes, and glycosomes are all related organelles that lack a genome and are bounded by a single membrane. However, the three types of microbodies exist in different cellular environments and possess distinct specialized functions.

If you have any desire to see the most boring webpage about glycosomes EVER, click here!

Peroxisomes
ddddThe enzymes and other proteins destined for peroxisomes are synthesized in the cytosol. Each contains a peroxisomal targeting signal (PTS) that binds to a receptor molecule that takes the protein into the peroxisome and then returns for another load.
dfdfdfFigure 1. A Typical Animal Cell
Here, the peroxisome is circled in pink and the cytosol is circled in green. Enymes for many metabolic processes are synthesized in the cytosol and transported into the peroxisome. Many other organelles are shown here and may serve as a reference, but not a point of study.

fffffff9

Glyoxysomes
dfdffdf A glyoxysome is aspecialized peroxisome containing the enzymes of the glyoxylate cycle. Glyoxysomes are articularly prevalent and important in germinating seeds. Glyoxysomes are in charge of the mobilization of stored energy compounds. Especially during growth, a large amount of carbohydrates are required for the synthesis of new cell walls.
ddddFigure 2: Energy Mobilization in Glyoxysomes
Triglycerides and aspartate enter the glyoxysome to be converted into succinate. The succinate is required in order for the energy-yielding process to contine through the mitochondria and finally to create sucrose in the cytosol.
dfdfdfdIn addition, malate can be shuttled directly into the cytosol to enter into a gluconeogenic pathway.
dddd
dddhjhjhhjjj 11

Glycosomes
dfdfdfTrypanosomatids have invented a new organelle not present in any other eukaryotic group! The glycosome is a specialized mircobody that contains most of the enzymes for the glycolytic pathway. Unlike a mammalian cell, the first nine reactions of glycolysis are organelle-associated.
dfdfdfThe glycosome is an undisputed member of the peroxisome family (Martin and Borst, 767) as it has the same structure, a single-bound membrane, and also uses targeting signals. Enzymes normally found within a plastid, and at some point "abandoned", have found a home inside of the glycosome!
Figure 3: Glycolytic Steps Inside Glycosomes
dddddThe purpose of Hannaert et al's work is to attempt to find genetic links between trypanosome glycolytic enzymes and plant or animal glycolytic enzymes. But the initial question they are trying to answer is, "Why are the steps of glycolysis sequestered into an organelle, the glycosome?" Below is a diagram of the nine steps that occur within the glycosome and the shuttles that allow compounds in and out.

dd(Parsons)