Topic
Galactolipase activity
About: Galactolipase activity is a research topic. Over the lifetime, 44 publications have been published within this topic receiving 976 citations.
Papers
TL;DR: The physiological role of HPLRP2 suggested by the present results is the digestion of galactolipids, the most abundant lipids occurring in plant cells, and therefore, in the vegetables that are part of the human diet.
Abstract: Human pancreatic lipase-related protein 2 (HPLRP2) was found to be expressed in the pancreas, but its biochemical properties were not investigated in detail. A recombinant HPLRP2 was produced in insect cells and the yeast Pichia pastoris and purified by cation exchange chromatography. Its substrate specificity was investigated using pH-stat and monomolecular film techniques and various lipid substrates (triglycerides, diglycerides, phospholipids, and galactolipids). Lipase activity of HPLRP2 on trioctanoin was inhibited by bile salts and poorly restored by adding colipase. In vivo, HPLRP2 therefore seems unlikely to show any lipase activity on dietary fat. In human pancreatic lipase (HPL), residues R256, D257, Y267, and K268 are involved in the stabilization of the open conformation of the lid domain, which interacts with colipase. These residues are not conserved in HPLRP2. When the corresponding mutations (R256G, D257G, Y267F, and K268E) are introduced into HPL, the effects of colipase are drastically reduced in the presence of bile salts. This may explain why colipase has such weak effects on HPLRP2. HPLRP2 displayed a very low level of activity on phospholipid micelles and monomolecular films. Its activity on monogalactosyldiglyceride monomolecular film, which was much higher, was similar to the activity of guinea pig pancreatic lipase related-protein 2, which shows the highest galactolipase activity ever measured. The physiological role of HPLRP2 suggested by the present results is the digestion of galactolipids, the most abundant lipids occurring in plant cells, and therefore, in the vegetables that are part of the human diet.
99 citations
TL;DR: This study examines the hydrolysis of galactolipids in vitro with human duodenal contents, pancreatic juice, and purified human pancreatic lipases to find MGDG, DGDG, and SQDG are all hydrolyzed by human Pancreatic juice.
89 citations
1 Jan 1995
TL;DR: In this paper, Andersson et al. examined the hydrolysis of galac-to-lipids in vitro with human duodenal contents, pancreatic juice, and purified human pancreatic lipases.
Abstract: Monogalactosyldiacylglycerols (MGDG), digalactosyl- diacylglycerols (DGDG) and sulfquinovmyldiacylglycerols (SQDG) are major lipids in vegetable food. Their digestion and absorp- tion are unknown. This study examines the hydrolysis of galac- tolipids in vitro with human duodenal contents, pancreatic juice, and purified human pancreatic lipases. Galactolipids were incubated with human duodenal contents, pancreatic juice, pure pancreatic carboxyl ester lipase (GEL), and colipase-dependent lipase with colipase (Lip-Col). Hydrolysis was estimated as release of free fatty acids and by the use of (3H)galactose or (3H)fatty acid-labeled DGDG. Pancreatic juice and duodenal contents hydrolyzed DGDG to fatty acids, digalactosylmono- acylglycerol (DGMG) and water-soluble galactose-containing compounds. The hydrolysis of DGDG was bile salt-dependent and had a pH optimum at 6.5-7.5. Human pancreatic juice released fatty acids from MGDG, DGDG, and SQDG. Purified CEL hydrolyzed all three substrates; the hydrolysis rate was MGDG > SQDG > DGDG. Pure Lip-Col had activity toward MGDG but had little activity against DGDG. Separation of pancreatic juice by Sephadex GlOO gel filtration chromatogra- phy revealed two peaks with galactolipase activity that coincided with CEL (molecular mass 100 kD) and lipase (molecular mass 50 kD) peaks. In contrast to pure Lip-Col enzymes of the latter peak were as active against DGDG as against MGDG. BP Thus, DGDG is hydrolyzed both by CEL and by a pancreatic en- zyme(s) with a molecular mass of 40-50 kD to fatty acids and lyso DGDG. MGDG, DGDG, and SQDG are all hydrolyzed by human pancreatic juice. Pure CEL hydrolyzed all three sub- strates.-Andersson, L., C. Bratt, K. C. Arnoldsson, B. Herslof, N. U. Olsson, B. Sternby, and A. Nilsson. Hydrolysis of galactolipids by human pancreatic lipolytic enzymes and duo- denal contents. J Lipid Res. 1995. 36: 1392-1400. cellular membranes because about 77% of the lipids are neutral galactosyldiacylglycerols (1). Of the total nonpig-
64 citations
TL;DR: The data suggest that the main physiological function of HPLRP2 is the hydrolysis of galactolipids, which are the main lipids present in vegetable food.
54 citations
TL;DR: A specific and continuous galactolipase assay using synthetic medium chain monogalactosyl diacylglycerol (MGDG) as substrate was developed using the pH-stat technique and recombinant human (rHPLRP2) and guinea pig (rGPL RP2) pancreatic lipase-related protein 2 as model enzymes found to significantly affect the rate of MGDG hydrolysis.
46 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 1 |
| 2017 | 1 |
| 2015 | 2 |