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Mechanisms of Hair Curvature
Curly Keratin
Hair composition is composed primarily of structural proteins, which make up 60-95% of its composition (Barthelemy et al. 2012). These proteins include keratin intermediate filaments (KIFs) and keratin-associated proteins (KAPs) that together form a matrix held together through disulfide, hydrogen, electrostatic, and amide bonds. The nature of these bonds renders hair more or less vulnerable to environmental stressors, such as sunshine, pollutants, and hair treatments.
Direct comparisons of the three main types of keratin, hair, epidermal, and simple type, revealed that hair is comparatively cysteine-rich (Strnad et al. 2011). These cysteines in turn play an important role in determining hair structure. For example, 97-98% of the cysteines in sheep wool have been shown to be involved in forming disulphide bonds. The proline content of hair KIFs is also relatively...
Together with the suggested role that the inner root sheath plays determining the shape of the developing hair strand, the cysteine composition of KIFs and KAPs would therefore play a significant role in helping to determining hair curvature.
The relative ratio of KIF to KAP composition also varies between the inner and outer sides of hair fibers, depending on an individual's ethnicity (Kajiura et al., 2006). For example, a greater contribution of KAPs to the inner portion of African-American hair explains its curly shape. This was…
Strnad, Pavel, Usachov, Valentyn, Debes, Cedric, Grater, Frauke, Parry, David A.D., and Omary, M. Bishr. (2011). Unique amino acid signatures that are evolutionarily conserved distinguish simple-type, epidermal and hair keratins. Journal of Cell Science, 124, 4221-4232.
Virtual Chembook. (2003). Permanent hair wave. Elmhurst.edu. Retrieved 18 Mar. 2012 from http://www.elmhurst.edu/~chm/vchembook/568hairwave.html.
Yu, Zhidong, Gordon, Steven W., Nixon, Allan J., Bawden, C. Simon, Rogers, Michael A., Widermoth, Janet E. et al. (2009). Expressiion patterns of keratin intermediate filament and keratin associated protein genes in wool follicles. Differentiation, 77, 307-316.
123). In this study, Martinez-Contreras and her associates report the results of recent research that has provided additional evidence concerning the function of these proteins in precursor-messenger RNA (pre-mRNA) splicing (2007). The splicing repression can function in two discrete ways in heterogeneous nuclear RNP proteins; the first way is by antagonizing the recognition of splice sites directly and the second way is through interference with the binding of proteins that
Biochemistry Similarity of Glycolysis in Prokaryotes and Eukaryotes Glycolysis is reported as being a pathway that is practically universal for energy extraction that carbohydrates hold available and this is true for eukaryotes, prokaryotes as well as aerobes and anaerobes. (Essential Biochemistry, 2014, paraphrased) Only eukaryotes have mitochondria. Some prokaryotes are reported to be photosynthetic and to use "an electron transport chain to make ATP." (Essential Biochemistry, 2014, p. 1) It is believed that
Biochemistry The Polypeptide Chain Configuration in Hemoglobin and other Globular Proteins By Linus Pauling and Robert B. Corey (1951) The article named above describes a continuation in the study of hydrogenbonded planar-amide configurations of polypeptide chains. It also discusses evidence on the possibility of the existence of such chains in fibrous proteins, and in molecules of globular proteins. The article first notes that globular patterns such as ovalbumin, can "on denaturation be converted into
Altogether, the Icelandic findings implicate epigenetic silencing of the BRCA1 gene in sporadic breast tumors. They even suggest that "the BRCA1 gene is implicated in sporadic breast tumorigenesis through epigenetic silencing and deletion of the BRCA1 gene," and that BRCA1 methylation is also found to be important in hereditary breast cancer, indicating similarities between BRCA1 methylated and hereditary BRCA1 breast tumors (Birgisdotter, et al. 9). While heredity factors strongly contribute
The next database used for the search is Medline. I began with the same search terms, celiac disease biochemistry, however it did not return any articles. Next, the search was expanded my search by simply searching celiac disease. This returned 544 articles. The first article is titled Celiac Disease and is from the National Library of Medicine. This article is clearly not useful. Next the search was expanded to celiac
student with a Bachelor of Science degree in Communications, minors in both Psychology and Sociology, and a desire to attend law school, my request to enter a Biochemistry program may be unusual. After all, people who focus on the hard sciences usually do so because of plans to work in a particular industry or to pursue additional field-specific education via Masters or PhD programs. Because I have no intention