Proteomics aids development of new hair care actives

The logic of protecting and replenishing the keratin proteins of the hair with keratin derivative, has experienced a major resurgence in the hair care market in recent times as care claims become more ‘high-tech’. KeramimicTM 2.0 takes biomimetic keratin one step further. This keratin quat treats ‘like with like,’ by mimicking the proteins found in the hair’s natural composition.

Product synthesis

Maintaining hair architecture at the molecular level is important to achieve healthy hair structure. Ultimately, proper hair protein structure has an important impact on the cosmetic value of the hair shaft. About 95% of human hair’s constitution is based on proteins, the majority of which are keratin proteins. Keratins belong to a multigene family that comprises more than 30 members. They are grouped into type-I acidic proteins and type-II basic to neutral proteins which form the 10 nm intermediate filament network in epithelial cells. Depending on their function and expression site, keratins can be divided into either the large group of epithelial cytokeratins (i.e. soft -keratins) expressed in the various types of epithelia or the hair keratins (i.e. hard -keratins), which are involved in the formation of hard keratinised structures such as hairs, nails, hoofs, and claws. The human hair proteome has been investigated using two-dimensional liquid chromatography and tandem mass spectrometry (LC-MS/MS). Several hundred proteins have been identified and fully sequenced, many of which are keratin proteins. These human hair keratin protein sequences are available on public databases such as UniProt (Universal Protein Resource). UniProt is a comprehensive, high-quality and freely accessible database of protein sequence and functional information. The database is a central access point for extensive curated protein information, including function, classification, and cross-reference (available at www.uniprot.org). Keratins are highly conserved proteins across species meaning there is high sequence homology within the keratin protein family. The term keratin protein covers a class of proteins which includes intermediate filament proteins (IFPs) and intermediate filament associated proteins (IFAPs) that are known to occur in nature in a variety of different cell types. The IFPs are so named because they have been found to be associated in intermediate filaments (IFs), a class of intracellular filamentous structures that are intermediate in size between microtubules and microfilaments. Keratin intermediate filaments consist of a globular head region, a highly conserved helical rod domain and a globular tail domain. The rod domain itself is composed of -helical segments, named segment Coil 1A, 1B and Coil 2A and 2B, which are separated from each other by globular linkers. It is this complex matrix of -helical protein bundles and amorphous protein junctions that are the basis for the special mechanical properties of the composite human hair. In the past, manufacturers have hydrolysed keratin protein sources using conventional methods to develop products that meet the ‘like with like’ trend. Croda has taken the next step forward to further build on this platform and to deliver advanced claims for the next generation of hair care products. Croda has targeted peptides in these -helical rod domains, which are responsible for the structural integrity of hair, as the foundation for Keramimic 2.0 (now referred to as ‘the biomimetic keratin quat’). Building on Croda’s extensive knowledge of biopolymer and keratin products, a new synthesis methodology has been developed in order to create defined molecular mass species from a keratin source. The first hurdle to overcome involves breaking the disulfide bridges present in keratin. These disulphide bridges create a helix shape that is extremely robust, as sulphur atoms from cysteine residues bond to each other from across the helix, creating a fibrous matrix which is not readily soluble. Once the disulphide bridges have been cleaved, a dual system of endoprotease and exopeptidase enzymes are used to hydrolyse keratin to yield the peptides of interest. The use of this novel synthesis process ensures the biomimetic keratin quat contains biofunctional peptides that replicate amino acid sequences naturally found in hair keratin proteins to repair and condition the most damaged areas of the hair cuticle. Croda has proven this using the science of proteomics. The peptide sequences of its keratin components were determined by tandem mass spectrometry technique (MS-MS), equipped with electrospray ionisation (ESI), time of flight (ToF) – MS in coupling with quadruple MS (ESI-QUAD-TOF-MS-MS). A basic local alignment search tool (BLAST) was used to screen each peptide to see which human hair keratin proteins contained the peptide in question. These biofunctional peptides are ideal chemical precursors for cationic conditioning agents as they contain amino functional groups as part of their structure. The final step in the process involves grafting quaternary ammonium groups onto the peptide backbone to become covalently bound. The resulting product is a mixture of biofunctional peptides with a chemically bound quaternary ammonium group, which imparts a cationic charge. These cationic groups enhance the product’s substantivity to anionic substrates, such as hair. As a result the product enhances consumer sensory and conditioning properties.