Carbohydrate Biochemistry 8| Tulane

Carbohydrate Biochemistry

• Glycated hemoglobin (HbA1C)
• Lactose intolerance
• Glycoprotein synthesis
• INfluenza virus Infection
• Heparin & heparan sulfate
• Peptidoglycans of bacterial wall

Glycate hemoglobin (HbA1C)

HbA1c is a consequence of high blood sugar (Glc) caused by diabetes

Normal Haemoglobin Fractions
Haemoglobin HbA (a2/b2): 95-98%
HbA2 (a2/d2): 1.5-3.5%
HbF (a2/g2): <2%
Several minor hemoglobins migrate more rapidly than
HbA in an electric field called HbA1.
HbA1 is made up of HbA1a + HbA1b + HbA1C.

What is HbA1C

	Suger	Terminal
HbA1a1	fructose-1,6 diphosphate	β - N-terminal
HbA1a2	glucose-6-phosphate	β - N-terminal
HbA1b	pyruvic acid	α- amino terminus
HbA1C	glucose attached	β - N-terminal

• HbA1C makes up >90% of HbA1.
• Normally less than 6% of Hb is HbA1C

How is HbAiC is formed

2 Glc residues -> Pre-HbA1C -> HbA1C

Note: Glucose is attache … to produce HbA1C molecules.

How can we detect Hb subspecies?

cation-exchange chromatography

Why is A1C clinically important?

• Disease marker for Diabetes

Lactose Intolerance

• Lactose intolerance

  • Inability to digest lactose.

• Lactose

  • Milk sugar, galactose - Glc

• Galactose (Gal)

  • C-4-epimer of Glc

• chemically link in Lactose

  • β-1,4-galactosidic linkage

• Cause of the lactose intolerance

  • Lack/deficiency of lactase(β-galactosidase)

• Biosynthesis

  • α-lactalbumin

Glycoproteins

Biosynthesis of O-glycans does not require dolichol phosphate.
Biosynthesis of N-glycans requires dolichol phosphate.

Synthesis

• Sialic aicd
• Hemagglutinin
• Neuraminidase

Three Major Type

• A: mammal and birds
• B & C: Human and not categorized into subtypes

Influenza Virus Infection

Type of Influenza viruses

Treatment of Influenza Virus Infection

Tamiflu and Relenza

Heparin and heparan sulfate

Fondaparinux