**3.1 Measurement of LOX activity in blood serum**

The activity of LOX was estimate in patients with stage pT3 colon cancer.

#### *Lipoxygenase and Colon Cancer DOI: http://dx.doi.org/10.5772/intechopen.99638*

The results of the study included the statistical values of colon cancer patients and the biochemical variables measured in patients and control group.

The results showed that there was an increase in the activity of LOX in the blood serum of patients with colon cancer. A statistical comparison between the effectiveness of LOX in patients' and control showed a significant excess in enzyme effectiveness in patients with probability P ≤ 0.0001 compared with control, as shown in **Figure 1**.

Overall, the results indicated an increase in the activity of LOX in the serum of colon cancer patients, previous scientific literature did not indicate that the enzyme's activity was measured from the serum of colon cancer patients, but indicated an increase in the activity of the enzyme in human colon cancer cell lines [28–30], this high effectiveness was reported to be highly correlated with reproduction of cancer cells, angiogenesis and resistance to apoptosis [31, 32].

Also the increase in enzyme activity is due to the increase in the digestion of unsaturated fatty acids and the release of Eicosanoid compounds that promote the growth of cancerous tumors [33].

Separation and Purification of LOX from Serum Patients of Colon Cancer: LOX was separated and purified in several steps as shown in the **Table 1**.

The first step was precipitating and separating the enzyme from blood serum by using ammonium sulfate salt at a concentration 0.40%. In the second step, the dialysis was performed to obtain a degree of purity and desalting. In the third step size-exclusion chromatography technique was used to purify the LOX from the proteins and other salts associated with the enzyme. The filtration column of the Sephadex G-100 resin was used in this step, a single peak was obtained at yield 71.42% and 11.033 times of purification as shown in **Figure 2**.

#### **Figure 1.**

*The effectiveness of LOX in sera of control and patient.*


#### **Table 1.**

*Separation and purification of the lox enzyme from serum patients of colon cancer yield.*

**Figure 2.** *Activity and absorbance at 280 nm for the fraction of gel filtration step of Sephadex G-100 resin.*

In the final ion exchange chromatography technique step was used to separate the LOX isoenzyme that based on the difference in charge. DEAE-Cellulose A50 resin was used, two isoenzymes were obtained with varying degrees of purity at a yield 28.57%, 21.42%, respectively and times of purification 16.372, 12.16 as shown in **Figure 3**.

It has been noted in previous scientific literature that LOX was purified from various sources such as the serum of patients with cardiovascular disease [34], with asthma [35] and with breast cancer [36].

Previous scientific literature has also indicated that the enzyme was purified from the colon cancer cell line [37] but did not indicate that the enzyme was purified from the serum of colon cancer patients. Also the scientific literature indicated that the enzyme was purified from various other sources, including
