Biochem Proteins

Classification of Proteins according to composition

Classification of Proteins according to Solubility

Classification of Proteins according to function

Composition of protein defined as naturally occurring

Composition of protein that is linked with nonprotein groups

Derivatives of proteins resulting from the action of enzymes, heat or chemical reagents

Consists of peptide chains compactly folded or coiled

Consists of long peptide chains or groups of such chains; coiled in spiral or helix formation

Fibrous proteins are cross linked by _________.

Linear sequence of amino acids; determines its 3D structure and its properties

Arrangement in the space of the atoms in the peptide backbone; arrangement of polypeptide chain into an organized structure

Secondary structure is stabilized by ______ between peptide.

Secondary structure bonds:

Coil direction; L-Amino Acid favor the right hand coil

Alpha helix H bonds occur between ___ O of backbone C=O to ___ H atom of backbone NH.

peptide backbone is almost completely extended

Two adjacent peptides

More common adjacent peptide and is rich in Alanine and Glycine (silk fiber and spider web)

Clusters held together by non-covalent interactions; combinations of secondary structure

Repetitive secondary structure

Combination of several motifs of secondary structures into a compact arrangement; 3D arrangement; noncovalent forces

Association of 2 or more polypeptide chains that may be identical or different to form a multi-subunit protein molecule

2 or more polypeptide chains

Almost identical subunits

Different subunits

Occurs after translation in the presence of molecular chaperones

Facilitates the protein folding

Prevent aggregation of heat-denatured proteins or polypeptides

Proteins responsible for structural support; H2O insoluble; examples are collagen, elastin, keratin

Proteins responsible for transport; H2O soluble; examples enzymes, antibodies, hormones

Proteins are highly expressed when cells are exposed to _______ temperature.

when a protein shape changes and goes back to primary structure because of high temperature

Newly found amino acids found in bacteria

Peptide bond via ________

Polymers of amino acids

A protein which assumes many forms; causative agent of mad cow disease

Biopolymers constructed from monomeric units knows as amino acids

Proteins needed in diet because the body cannot synthesize them

Proteins needed by the body but can be manufactured or synthesized by the body

<100 amino acids

> or = to 100 amino acids

Charged/polar R-groups generally _____________ on soluble proteins

Nonpolar R-groups tend to be ___________ in the cores of soluble proteins.

Membrane proteins have adapted to __________ environments.

Misfolded proteins problems:

The _______ of amino acids determines its distinct chemical and biological properties.

The only amino acid that is not chiral.

Nonpolar side chains

Neutral Polar side chains

Most amino acids prefer the __ configuration.

For higher levels of protein structure, they are determined using __________ techniques. While for primary structure, use __________ methods.

Before protein sequencing, it is necessary to remove first the ________ bonds.

Sanger technique uses ____________ which reacts with the N terminal residue under alkaline conditions.

Edman technique uses _______________ which derivatizes the N terminal amino acid residue but still leaves the rest of the chain sequence intact.

Trypsin cleaves at

Pepsin cleaves at

Chymotrypsin cleaves at

Carboxypeptidase cleaves from __ terminus while aminopeptidase cleaves from __ terminus.

Protein isolation based on charge

Protein isolation based on molecular size

Protein isolation based on selective binding to a specific molecule; use of antigen and antibodies

Protein isolation based on charge and molecular size

Protein isolation based on isoelectric point of the protein; done in serum samples

Used as support medium for low molecular weight biochemicals such as amino acid and carbohydrates

Used as support medium for large molecules like nucleic acids and proteins

The larger the protein, the more of the ______ it absorbs.

Used to completely denatures protein in protein gel electrophoresis method

In chemical precipitation, ______ tend to precipitate, leaving _______ in the solution.

An ion exhange chromatography that begins at a basic pH; net negative charge

An ion exhange chromatography that begins at an acid pH; positive charge adhering to negative charge

Add _____ to make negative to positive

Proteins with more negative charge move ______

If proteins contain more than ___ polypeptide chain, chains are separated and purified.