CARBOHYDRATE Lecture (Slides 1-20)

Overview of Carbohydrates and Glycosidic Bonds

• Introduction to Pharmacy Background

  • Mention of pharmacy school experience

  • Previous knowledge in pharmaceutics, pharmacology, and medicinal chemistry

Macromolecules

• Review of Proteins

  • Studied proteins primarily from the perspective of amino acids

  • Discussed protein structures, including primary structure

  • Focus on enzymes in proteins

  • Types of enzymes and their functions

  • Enzyme classes and reactive classes

  • Reactions they metabolize

  • Interaction of amino acids in active sites through noncovalent interactions

  • Discussion on enzymatic conversions and energetics

  • Key concepts in enzyme kinetics:

  • Inhibition (competitive and noncompetitive)

  • Km and Vmax in enzyme comparisons

• Transition to Carbohydrates

  • Introduction to the next major macromolecule: Carbohydrates

Learning Objectives for Carbohydrates

• Study framework for carbohydrates:

  • Monosaccharides, disaccharides, and polysaccharides

  • Functions of carbohydrates

  • Chemical fundamentals - introduction to terms related to carbohydrate structures

Carbohydrate Definitions

• "Carbohydrate" etymology: hydrated carbon

  • Chemical structure formula:

  • General formula: $C<em>nH</em>{2n}O_n$ (not required to memorize)

• Classification based on the number of sugar units:

  • Monosaccharides (1 sugar)

  • Disaccharides (2 sugars)

  • Oligosaccharides (3 to 10 sugars)

  • Polysaccharides (11 or more sugars)

Solubility of Sugars

• Water solubility trends among carbohydrate types

  • Small sugars (monosaccharides and disaccharides) are highly water soluble

  • Larger sugars like starch are less soluble

  • Size impacts solubility

Monosaccharide Classifications

• Further categorization by the number of carbon atoms:

  • Triose (3 carbons), Tetrose (4 carbons), Pentose (5 carbons), Hexose (6 carbons), Heptose (7 carbons)

• Examples of monosaccharides:

  • Triose: Glyceraldehyde

  • Tetrose: Erythrose

  • Pentose: Ribose

  • Hexose: Glucose, Fructose

• Aldose and Ketose Definitions:

  • Aldose: Contains an aldehyde group (ending in -ose)

  • Ketose: Contains a ketone group

D and L Nomenclature

• Understanding D/L nomenclature for sugars

  • D-sugars based on the orientation of the penultimate carbon

  • All sugars considered are D-sugars in this context

Isomerism in Sugars

• Isomers: Same molecular formula but different structures

• Epimers and Enantiomers:

  • Epimers: Differ in configuration at one specific carbon atom (except carbonyl carbon)

  • Example: Glucose and Galactose - C4 epimers

  • Enantiomers: Mirror images that are non-superimposable

  • Example: Glucose and Galactose, Mannose and Glucose

Reaction Mechanisms: Formation of Hemiacetals and Hemiketals

• Hemiacetals: Form when an aldehyde reacts with an alcohol

  • Carbon connected to two oxygens: one from the aldehyde, one from the alcohol

• Hemiketals: Form when a ketone reacts with an alcohol

• Importance of structure and mechanism

Cyclic Sugars

• Sugars exist chiefly in cyclic forms due to stability

• Role of anomeric carbon in cyclic sugars

  • Anomeric carbon definition and significance

  • Formation of pyranose and furanose structures

  • Pyranose: 6-membered ring, common for hexoses

  • Furanose: 5-membered ring, common for pentoses

Glycosidic Bonds and Disaccharides

• Formation of glycosidic bonds from monosaccharides

  • Connection via anomeric carbon of one monosaccharide and a hydroxy group of another

  • Glycosidic bond type: ether linkage, with examples relating to food

• Process of condensation (loss of water during bond formation)

Concluding Remarks on Structure and Function

• Importance of knowing sugar structures and linkages for understanding metabolic processes

• Relevant biological implications of glucoregulation and enzyme activities!

  • Relationship of disaccharides and polysaccharides to metabolism