Glycoproteins

Covalently bound carbohydrates (Conjugated Protein)

Lipoproteins

Covalently bound to lipids (conj. protein)

Metalloprotens

metal ions (trace minerals) for structure stabilization or catalytic function (conj. proteins)

Phosphoproteins

Covalently bound phosphate groups used to activate/deactivate a protein or provide binding sites for protein attachment (conj. proteins)

Hemoproteins

contain heme groups/pophyrin rings (conj. proteins)

Nucleoproteins

contain ribonucleic acids (conj. proteins)

Enzyme

biological catalyst (protein or RNA)

Substrate

reactant of enzyme catalyzed reaction

Turnover number

Number of substrate molecules converted to product over time

Cofactor

nonprotein that binds to protein, required for catalysis

Coenzyme

organic cofactors typically in Redox enzymes (vitamins)

Apoenzyme

protein minus cofactor/coenzyme

Holoenzyme

catalytically active enzyme (apoenzyme with cofactor/coenzyme)

Active site

pocket in enzyme where catalysis takes place

Oxidoreductases

catalyze oxidation-reduction reactions

Transferases

transfer of functional group (amino or phosphoryl) between substrates

Hydrolases

catalyze hydrolysis of substrates (water lysis)

Isomerases

catalyze isomerization of substrate (rearranges bonds of substrate)

Lyases

catalyze elimination of a functional group by forming a double bond or breaking a double bond

Ligases

catalyze bond formation couple with ATP hydrolysis

Lipases

hydrolyze ester bonds in lipids (hydrolase)

Proteases

hydrolyze peptide bonds (backbone amides) in proteins

Nucleases

hydrolyze phosphate ester bonds in DNA/RNA (hydrolase)

Amylases

hydrolyze 1, 4 glycosidic bonds in amylose (hydrolase)

Kinases

transfers a phosphoryl group (-PO3²-) between substrates (transferase)

Transaminase

transfers amino group (-NH3+) between substrates (transferase)

Dehydrogenases

removes 2 hydrogen atoms from a substrate to form double bond (requires coenzyme: FAD or NAD+)

Competitive Inhibition (reversible)

Inhibitor resembles substrate, competes for same binding site on enzyme

Noncompetitive inhibition (reversible)

Inhibitor binds to separate site on enzyme, does not resemble substrate

Uncompetitive inhibition (reversible)

Inhibitor binds to separate site on enzyme, does not resemble substrate

Irreversible Inhibition

Covalent modification of enzyme rendering it inactive

Allosteric Regulation

Substrate binding effected by binding of a molecule at a different site

Feedback control

Product in metabolic pathway is an allosteric regulator of an enzyme that catalyzes a critical step in that pathway

Covalent modification

addition of phosphate group on tyrosine, serine, threonine can trigger conformational change in enzyme structure, activates or deactivates enzyme

Zymogens

Enzyme synthesized as an inactive form (proenzyme), which has a longer protein segment that must be removed before enzyme is active

Genetic control

Gene for an enzyme is turned off or on to regulate the amount of enzyme present in cell

Energy effect

lower activation energy by inducing strain on bonds of substrate

Catalytic effect

provide acidic, basic, other types of functional groups required for catalysis

What are the parts of an amino acid?

Amine group, carboxylic acid group, alpha carbon, side chain

Constitutional Isomer

different bonding order of atoms

Stereoisomer

atoms bonded in same order, different arrangements

Enantiomers

mirror images of stereoisomers, not superimposed

Diastereoisomers

not mirror images, not superimposable

Nonpolar amino acids

side chains alkanes, arenes (no charge)

Hydrophobic - van der waals

Neutral polar amino acids

side chains hydroxyl, thiol, amide (no charge)

Hydrophilic - h bonding

Acidic amino acids

side chain has carboxylic acid group (negative charge)

Hydrophilic - electrostatic (ionic)/hydrogen bonds

Basic amino acids

side chain has amine group (positive charge)

hydrophilic - electrostatic (ionic)/hyrogen bonds

Zwitterions

both positive and negative charges, all amino acids at pH 7

Glycine

no organic side chain, flexible, located in turns

Proline

secondary amine, forms tertiary amine upon formation of peptide bond

Cysteine

thiol group forms disulfide gonds in extracellular proteins, binds metals