Human biochem lecture 9

Phenylketonuria (PKU)

An autosomal recessive disorder characterized by inability to convert phenylalanine into tyrosine due to a genetic mutation in the phenylalanine hydroxylase gene.

Amino Acid

Organic compounds that serve as the building blocks of proteins; each has an amino group, a carboxyl group, and a unique side chain.

Essential Amino Acids

Amino acids that cannot be synthesized by the body and must be obtained through diet; includes isoleucine, leucine, valine, lysine, methionine, threonine, phenylalanine, and tryptophan.

Non-essential Amino Acids

Amino acids that can be synthesized by the body and do not need to be obtained directly from the diet.

Peptide Bond

A covalent bond formed between the amino group of one amino acid and the carboxyl group of another, resulting in the release of a water molecule.

Catalytic Domain

The region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Toxic Build-up

Accumulation of substances that can be harmful to the body, often due to impaired metabolic processes.

Neurotransmitters

Chemicals that transmit signals across a synapse from one neuron to another, essential for various nervous system functions.

Codon

A sequence of three nucleotides in mRNA that specifies a particular amino acid for protein synthesis.

Hydrophobic Amino Acids

Amino acids that do not interact favorably with water, often located in the interior of proteins.

Cysteine

An amino acid that is important for forming disulfide bonds, contributing to protein structure stability.

Selenocysteine

An amino acid that is considered the 21st amino acid; incorporates selenium into proteins.

Post-translational modification

Changes made to a polypeptide chain after translation, including folding, cleavage, and chemical modifications.

Secondary Structure

The local folded structures that form within a polypeptide due to hydrogen bonding, such as alpha helices and beta sheets.

Metastable

Referring to a state that is stable under certain conditions but can change if a catalyst or different conditions are introduced.