BIOC 223

I’m glycine, and together, we make a peptide!!!!

(Actual blog post coming soon.)

Just as I was mentioning that the semester is ending soon while studying biochemistry in Stone D, Zoe “shh”-ed me and I immediately thought of cysteine.

(I’m cysteine.)

Today, I was working in Stone D with my lipids group on our exam question re-dos, when I saw three Wellesley students get up from their table holding hands and wind their way through the dining hall tables. Being tired and biochemistry-absorbed, my first thought was that their hands were like peptide bonds, and they were like a polypeptide moving in solution (air)! We thought this was funny.

(I’m isoglutamate. This will make more sense after you read Part II and III!)

This weekend, I was getting a few things from CVS when I came across “natural, aluminum-free” deodorant. I’d never heard of this before and had no idea why it would be a selling point so I looked it up. It turns out that the active ingredient aluminum is suspected to cause breast cancer and there have even been studies done to find out if it is true or not (http://www.ncbi.nlm.nih.gov/pubmed/22995589).

Though research so far has not been very definitive, it seems that aluminum might be toxic to DNA and interfere with estrogen receptors. Estrogen promotes the growth of breast cancer, and the pathway involves ligand-activated zinc fingers, which we’ve talked about in class! (http://www.ncbi.nlm.nih.gov/pubmed/16045991)

I thought it was so interesting how much of this chemistry we know from what we’ve learned in class. Also, it’s super applicable because we all use deodorant (I hope) so it truly affects all of us. Right now, research points to no adverse effects, though there hasn’t been enough research done to determine long-term effects and definitively conclude that there is no relationship between aluminum salts and breast cancer. So it may be wise to switch to an aluminum-free deodorant for the time being.

We’ve talked a lot in both lab and lecture about the importance of considering environmental effects in an experiment. I was thinking recently about two of the major obstacles we have discussed: pH levels and the presence of ions/salts. The water at Wellesley is horrifyingly hard, as my hair can demonstrate. if you leave some tap water out in an open container, it will evaporate away and leave a thin white film. This white film is calcium carbonate, which is the primary source of water hardness and has a pKa of 9.0, making it basic. One of the reasons we are so concerned about environmental conditions in our lab experiments is because pH levels and excess ions in solution can interfere with noncovalent bonds between proteins. Case in point: Human hair is composed of long, fibrous strands of proteins called keratin. These proteins undergo a variety of noncovalent bonds, notably disulfide bonds, which keep hair appearing happy and healthy. The ions and basicity of hard water can contribute to breaking disulfide bonds, which leads to damaged hair, ,split ends, and one unhappy Lynn. In summary, I think I need a better conditioner…

We have been talking A LOT in class about the “standard” 20 amino acids. Recently, I had a conversation with my dad that got me thinking about one amino acid in particular: glutamic acid. More specifically, we were discussing the sodium salt of glutamic acid, monosodium glutamate, which is commonly known as MSG.

My family is Chinese American, and we love eating traditional Chinese foods where MSG is a common ingredient. I’ve talked with my father previously on the pros and cons of using MSG in foods, but I’ve never had sufficient scientific background to really consider what I was putting in my mouth every time I chose to go eat some takeout. According to Wikipedia and the NYT, MSG is used in dishes to enhance savory flavors and to achieve what the Japanese call “umami” – the fifth flavor distinct from sweet, salty, bitter, and sour. It is a synthetic salt analog to the many types of L-glutamate that occur naturally in many foods, such as kelp.

I’ll admit it – I like the flavor of MSG. To me, it tastes of pure, distilled sea food, like all of the savory flavors in a dish have been magnified x10. As an ingredient, however, it remains controversial. I’m really interested in learning more about amino acid properties in class to see if maybe I can learn more about MSG. Maybe it’s time to cut back on Japanese and Chinese food?

If anybody is interested, here’s an old article NYT published on the subject:  http://www.nytimes.com/2008/03/05/dining/05glute.html?pagewanted=2&_r=0&sq=msg&st=nyt&scp=1

Spending most of this week learning about proteins and their structures, I am starting imagine little amino acid residues in the food we eat. We are always told that meant has a lot of proteins or egg whites are good for us cause of their proteins. I looked into this since I want to know what types of protein that I have been ingesting every morning. After performing a google search, I found that egg whites are 90% water with 10% proteins, mostly albumins, mucoproteins, and globulins. Since water is polar, I now know that amino acids on the surface that interact with water should be polar or charged while those that are held in the core would be nonpolar. In fact what we learn in Biochem class are everywhere. They are now taking over the image of food in my mind!