| Revision as of 03:08, 29 May 2007 editBigshuannie (talk | contribs)22 editsNo edit summary← Previous edit | Latest revision as of 12:55, 6 October 2017 edit undoEvolution and evolvability (talk | contribs)Extended confirmed users24,410 edits merge and redirect to Pancreatic lipase family#Human pancreatic lipaseTag: Visual edit | ||
| (24 intermediate revisions by 16 users not shown) | |||
| Line 1: | Line 1: | ||
| #REDIRECT ] | |||
| Steapsin belongs to the class of digestive enzymes called lipases found in the pancreatic juice that catalyzes the hydrolysis of triglycerides (main constituent in vegetable oils and animal fat) to fatty acids and glycerol. When food travels through the oral cavity and down the esophagus into the stomach, enzymes such as pepsin are released where it cleaves large proteins into smaller peptide fragments so further digestion and absorption can occur in the duodenum, the tube that connects the stomach to the small intestine. Fats are minimally digested in the stomach by gastric lipases but most digestion occurs in the small intestine. | |||
| ] | |||
| == Function == | |||
| The lipase steapsin is secreted from the pancrease to break down triglycerides to liberate the fatty acids and glycerol. The free fatty acids can then be absorbed to the liver and kidneys where it may be converted to glyceraldehyde 3-phosphate, a constituent in the process of glycolysis to ultimately generate energy in the form of ATP via the citric acid cycle. Fatty acids that are not used for energy can then be allowed to cross the intestinal barrier to be repackaged into fatty tissue. | |||
| == Characterization == | |||
| Previous studies have shown some physical characteristics of steapsin. Throughout this experiment, steapsin was found to be inherently unstable and will degrade naturally. | |||
| == Method == | |||
| To quantify the activity of steapsin in vitro, olive oil was used as the fat (triglycerides) to be broken down. Steapsin was added and various experiments were conducted which thus digested olive oil to form glycerol and free fatty acids. The free fatty acid formation caused the mixture to turn acidic, thus phenolphthalein indicator was added and the mixture was titrated against 0.1M NaOH. Therefore, the steapsin activity correlates to the amount of NaOH added, and subsequent experiments can be quantified and compared this way. | |||
| A. pH | |||
| • Basic conditions – 10% steapsin degradation per hour | |||
| • Neutral conditions – 10% steapsin degradation per hour | |||
| • Acidic conditions – 0.02M of HCl decreased steapsin activity by 80% | |||
| B. Temperature | |||
| • 37 C – 8% degradation per hour | |||
| • 40 C – 10% degradation per hour | |||
| • 50 C – 99% degradation per hour | |||
| • 60 C – 99% degradation in 10 minutes | |||
| C. Trypsin (Steapsin inhibitor) | |||
| • Produced in pancreas and secreted as trypsinogen (inactive precursor of trypsin) | |||
| • Trypsin activated by enteropeptidase (secreted from duodenum) to prevent autodigestion of the pancreas. | |||
| • Trypsin inactivates steapsin | |||
| D. Egg Albumen (Trypsin inhibitor) | |||
| • When trypsin, steapsin and egg albumen present in solution, trypsin is neutralized | |||
| • Steapsin activity unchanged | |||
| E. Bile | |||
| • Bile does not hydrolyse fats independently, acts as emulsifier, providing greater surface area | |||
| • Combined with steapsin, activity increased by nearly two fold | |||
| Conclusions | |||
| When eating greasy foods: | |||
| 1. Eat protein (e.g. egg whites, lean meat) to allow steapsin to remain active for a longer period to break down triglycerides. | |||
| 2. Remember to expend the energy from these fatty acids to prevent it from being incorporated into adipose tissue. | |||
Latest revision as of 12:55, 6 October 2017
Redirect to: