Phosphate Ester Formation Hydroxyl group + H3PO4 --> Phosphate Ester Phosphate esters are important compounds in carbohydrate metabolism.

Phosphate ester formation -D-glucose-1-phosphate Sugar and phosphate combinations are the basis for nucleotides involved in DNA / RNA, energy carrying molecules (ADP & ATP), and chemical messengers (cAMP) Henna and  Glucose-6-phosphate dehydrogenase deficiency: Catherine Cartwright-Jones c 2004  Kent State University Henna can cause a haemolytic crisis in G6PD deficient infants.  G6PD deficiency is an inherited condition, and any infant who is diagnosed with this condition MUST NOT have henna.  Henna can cause severe anemia in G6PD deficient infants by penetrating their thin, fragile skin of infants and causing oxidative haemolysis of their blood cells. G6PD deficiency is a recessive x-chromosome sex-linked inheritable trait. If males have that trait on their x chromosome, they will be affected.  For females have the trait on one of their x chromosomes, they will not be affected.  If both of a female's x chromosomes are G6PD deficient, they will be affected.  Therefore, in populations that have G6PD deficient individuals, males will be twice as likely to be adversely affected by henna as females.  The populations that have this trait are mostly in the Middle East and North Africa. This may be why men rarely have henna, or have henna in small applications, while women have extensive and frequent henna in those regional traditions.  The natural red tannin dye in henna is Lawsone (2-hydroxy-1,4 napthoquinone).  This is similar in structure to 1,4 napthoquinone, a naphthalene metabolite which strongly oxidizes G6PD deficient cells. Strong oxidants, such as are found in fava beans and naphthalene fumes (most commonly encountered in mothballs) cause similar haemolytic crisis in children, and in large amounts, can endanger G6PD deficient adults. G-6-PD deficiency is an inheritable, X-linked recessive disorder whose primary effect is the reduction of the enzyme G-6-PD in red blood cells, causing destruction of the cells, called hemolysis. Ultimately, this hemolysis leads to anemia -- either acute hemolytic or a chronic spherocytic type. In the United States, many more black than white people have the disorder. Approximately 10-14% of the black male population is affected. The disorder may occasionally affect a black women to a mild degree (depending on their genetic inheritance). People with the disorder are not normally anemic and display no evidence of the disease until the red blood cells are exposed to an oxidant or stress.

Amino Sugar Formation Hydroxyl group is replaced by an amino group --> Aldosamine Important in cartilage polysaccharides and red blood cell markers (ABO) There are 3 important, naturally-occurring amino sugars. In each the amino group is on C#2.

Amino sugar formation Glucosamine and hyaluronic acid act as the backbone for the formation of proteoglycans found in the structural matrix of joints

Glycosidic bonds: R-OH + HO-R'  R-O-R' + H2O The hydroxyl group and a hydroxyl group of another sugar or other compound can join together, splitting out water to form a glycosidic bond. R-OH + HO-R'    R-O-R' + H2O Acting hemiacetal Acting as an alcohol glycosidic linking helps form disaccharides, oligosaccharides, and polysaccharides from rings of monosaccharides

Disaccharide formation oligosaccharides not usually free, but covalently linked to protein or lipid "glycoconjugates" mannose very common usually very branched modified sugars very common, especially w/ charges mucins, proteoglycans polysaccharides energy storage - 1 large soluble molecule better than 1000's of small ones starches amylose: glc's linked by a(1,4) bonds chains form helices - open center amylopectins: a(1,4) chains plus a(1,6) branches (~20 - 24 residues) more soluble, why? glycogen: like amylopectin but more branches (~10 - 12 residues) structure cellulose: glc's linked by b(1,4) bonds flat sheets, insoluble, why? chitin: glcNAc linked by b(1,4) bonds Alpha () or beta () describes the –OH orientation on C #1. The numbers represent the C # connections on the Haworth projection

Disaccharides Formation of disaccharides is like glycoside formation (condensation rxn) Monosaccharide + alcohol --> glycoside + H2O Monosaccharide + monosaccharide --> disaccharide + H2O Disaccharide glycosidic linkage Reducing? Human Digestion Maltose (1-4) yes easily Cellobiose (1-4) yes no Lactose (1-4) yes usually Sucrose (1-2) no yes

Common Disaccharides: Sucrose: a-Glucose and b-Fructose a, b (12) glycosidic linkage Milk sugar: galactose and glucose connected a(14) glycosidic linkage of 2 D-Glucose molecules

Polysaccharides (glycan) Variations Homopolysaccharides vs. Heteropolysaccharides Length of chain Type of Glycoside Linkage Degree of Branching Properties NOT sweet No positive Tollens or Fehling’s test Limited water solubility Colloids form readily

Storage Polysaccharides energy source (homopolysaccharides) Starch (plants) amylose (15-20%) straight-chain -glucose polymer (~1000 G) amylopectin (80-85%) branched chain (~100,000 G) glucose polymer (~100,0000 G) Starch + H2O --> glucose Nutritional value Glycogen (animals) Highly branched glucose polymer (~1,000,000 G) Glucose <==> Glycogen (stored in liver & muscle)

Cellulose

Structural Polysaccharides (homopolysaccharides) Cellulose (cell wall) straight chain -glucose polymer Chitin (exoskeleton) N-acetyl amino derivative of glucose

Cotton and wood are primarily cellulose (14) glycosidic bonds of two glucose rings create linear but angled bonding. Our enzymes cannot match this bond angle structure to hydrolyze cellulose into cellobiose subunits or break that down to glucose

Acidic Polysaccharides (heteropolysaccharides) Hyaluronic acid Joint lubricant Heparin Anticoagulant Hyaluronic acid: heteropolysaccharide – 2 different glucose derivatives: Glucuronic acid plus N-acetyl-b-D-Glucosamine Alternates b(13) and b(14) linkage Acidic polysaccharides associated with the connective tissue of joints give hurdlers such as these the flexibility needed to accomplish their task.

Glycolipids & Glycoproteins These form when glycosidic linkages connect monosaccharides with lipids &/or proteins. Very important molecules for cell recognition processes

Dietary Considerations A balanced diet ~ 60% carbohydrate Simple carbs = mono & disaccharides Complex carbs = polysaccharides Starch Cellulose Natural vs. Refined Sugars Natural: a mixture of sugar and other compounds Refined: 100% sugar molecules Glycemic effect: due to the rate of carbohydrate digestion Glycemic index

Glycemic Index: Measures the rate that specific carbohydrates are hydrolyzed into glucose. Slow release of glucose into blood = good Quick release of glucose into blood / overproduction of insulin = bad