Notes in Digestion of Carbs/Proteins

To Subscribe, use this Key

Status	Last Update	Fields
Published	01/20/2024	Digestion of carb enzymes:{{c1::pancreatic alpha-amylase (endo-glycosidases)enzymes on brush border}}
Published	01/20/2024	Enzymes on the brush bordermembrane cleave {{c1::dextrins}}
Published	01/20/2024	{{c1::Sucrase}} and {{c1::isomaltase}} are twoenzymes from a single protein;associated in the cell membrane →sucrase-isomaltase (SI) complex
Published	01/20/2024	These are both brush borders:{{c1::maltase}} cleaves maltose while {{c1::glucoamylase}} cleavesα(1→4) linkages from dextrins
Published	01/20/2024	Brush border enzymes are produced by the {{c1::intestinal mucosal}} cells.
Published	01/20/2024	Mouth: {{c1::alpha-amylase}} breaks alpha(1→4) bonds.
Published	01/20/2024	In duodenum, bicarbonate from pancreas neutralizes acid; pancreatic alpha-amylase works with {{c1::glucoamylase}} + {{c1::disaccharidases}} (brus…
Published	01/20/2024	35db0825291a40359a5a7315dc55f6fb-ao-1
Published	01/20/2024	35db0825291a40359a5a7315dc55f6fb-ao-2
Published	01/20/2024	35db0825291a40359a5a7315dc55f6fb-ao-3
Published	01/20/2024	35db0825291a40359a5a7315dc55f6fb-ao-4
Published	01/20/2024	35db0825291a40359a5a7315dc55f6fb-ao-5
Published	01/20/2024	In human nutrition, cellulose acts as a hydrophilic bulking agent forfeces and is often referred to as "dietary fiber". Humans don’t have {{c1::beta-(…
Published	01/20/2024	Some animals, particularly ruminants (e.g., cattle, goat and sheep)and termites, can digest cellulose with the help of symbiotic micro-organisms that …
Published	01/20/2024	{{c1::Sucrase-isomaltase deficiency}}: It has a prevalence of 0.02% inindividuals of the European descent. It is {{c2::autosomal recessive}}. Thecondi…
Published	01/20/2024	Symptoms for {{c1::Sucrase-isomaltase deficinecy}}:- Abdominal cramps and bloating- Diarrhea- Vomiting- Hypoglycemia and headaches- Poor weight gain a…
Published	01/20/2024	{{c1::More than a half}} of world’s adultpopulation has lactose intolerance
Published	01/20/2024	Causes for lactose intolerance:- Expression of the LCT gene is altereddue to {{c1::DNA methylation}};- Mutation in the LCT gene (rare)
Published	01/20/2024	{{c1::Duodenum}} and {{c1::jejunum}} absorb dietary sugars. Only {{c2::mono-saccharides}} can be absorbed
Published	01/20/2024	Insulin {{c1::not}} required for uptake by intestinal cells.
Published	01/20/2024	{{c1::GLUT1}} and {{c1::GLUT3}} mediate basal glucoseuptake in most tissues, including {{c2::brain, nerves,and red blood cells}}
Published	01/20/2024	GLUT2 is a low-affinity transporter in {{c1::hepatocytes}}, {{c1::beta cells}}, and {{c1::epithelial}} cells of small intestine and kidney tubule…
Published	01/20/2024	When the glucose concentration drops below its {{c1::Km}}, most glucose leaves the liver & enters the peripheral circulation
Published	01/20/2024	In the β-islet cells of the pancreas, GLUT2, along with glucokinase,serves as the glucose sensor for {{c1::insulin}} release
Published	01/20/2024	Insulin secretion by the pancreatic β-cells is biphasic.1) First phase (within 15 min) withrelease of {{c1::preformed insulin}}.2) Second phase (sever…
Published	01/20/2024	GLUT4 is in {{c1::muscle}} and {{c1::adipose}} tissue; high affinity for glucose
Published	01/20/2024	The rate of glucose transport in muscle/adipose is increased by{{c1::insulin}}, which stimulates the movement of additional GLUT4transporters to the m…
Published	01/20/2024	Proteins are too large to be absorbed;must be hydrolyzed first. Hydrolysis isaccomplished by enzymes from 3different organs:- stomach: {{c1::pepsin}}-…
Published	01/20/2024	{{c1::Endopeptidases}}: proteolytic peptidases that break peptide bonds of nonterminal amino acids (i.e., within the molecule). Ex: Trypsin, chymotryp…
Published	01/20/2024	{{c1::Exopeptidases}}. peptidases that catalyze the cleavage of theterminal (or the penultimate) peptide bond. Ex: Aminopeptidase,carboxypeptidases, d…
Published	01/20/2024	{{c1::HCl}} (pH 2-3) too dilute to hydrolyze proteins, serves to kill some bacteria and denature proteins
Published	01/20/2024	{{c1::pepsin}}: acid-stable endopeptidasesecreted as pepsinogen, activated by acid or pepsin
Published	01/20/2024	Release of zymogens from pancreas: stimulated by {{c1::CCK(Cholecystokinin)}}, a peptide hormone from the small intestine (Icells).
Published	01/20/2024	CCK → {{c1::the exocrine cells of the pancreas}} (causing them torelease digestive enzymes)
Published	01/20/2024	CCK → the gallbladder (causing it to contract and release{{c1::bile}} - a mixture of bile salts, phospholipids, and free cholesterol)
Published	01/20/2024	Secretion of pancreatic juice: secretin is produced by the {{c1::Scells}} of the duodenum
Published	01/20/2024	secretin → the pancreas: release a solution rich in {{c1::sodiumbicarbonate}}; helps neutralize pH of the intestinal contents
Published	01/20/2024	secretin → bile ductules and ducts: increase {{c1::water and HCO3- secretion}}
Published	01/20/2024	{{c1::Enteropeptidase}} (also called enterokinase) produced by thecells in the duodenum cleaves trypsinogen → trypsin
Published	01/20/2024	{{c1::trypsin}} can also cleave trypsinogen, and {{c1::trypsin}} is the common activator of all the zymogens, so enteropeptidase begins acascade of pr…
Published	01/20/2024	Without pancreatic enzymes -− 60% fat not absorbed ({{c1::steatorrhea}})− 30-40% protein and carbohydrates not absorbed
Published	01/20/2024	{{c1::Exopeptidases}} catalyze the cleavage of the terminal (or thepenultimate) peptide bond and release amino acids anddipeptides
Published	01/20/2024	Two groups of Exopeptidases {{c1::Aminopeptidases}}{{c1::Carboxypeptidases A and B}}
Published	01/20/2024	{{c1::Carboxypeptidases A and B}} produced by the pancreas andactivated in the intestine
Published	01/20/2024	{{c1::Aminopeptidases}} are produced by glands of the small intestineand resides on lumenal surface of the small intestine. Many ofthese peptidases ar…
Published	01/20/2024	Dipeptides and tripeptides are cleaved in the {{c1::cytoplasm}} bydipeptidases and tripeptidases before entering portal system
Published	01/20/2024	only free {{c1::amino acids}} are found in portal vein; these aremetabolized by liver or released into circulation
Published	01/20/2024	3 Types of Transporters1. {{c1::Na+ -dependent symporters}}2. {{c1::H+ dependent symporter}}3. {{c1::Na+ independent transporter }}
Published	01/20/2024	{{c1::Na+ -dependent symporters}},linked to ATP-dependent pumping out of Na+ at the contraluminalmembrane.
Published	01/20/2024	{{c1::H+ -dependent symporter}} transports di- and tripeptides.Export, via the basolateral membrane
Published	01/20/2024	{{c1::Na+-independent transporters}}, allowing facilitated transport of amino acids to the hepatic portal system
Published	01/20/2024	Neutral amino acid symporter for aromatic or hydrophobic side chains({{c1::Phe, Tyr, Trp, Met, Val, Leu, Ile}})
Published	01/20/2024	These transport systems are present in the {{c1::small intestine}} and in the {{c1::proximal tubule}} of the kidney
Published	01/20/2024	Basic amino acid symporter ({{c1::Lys, Arg, Cys}})
Published	01/20/2024	{{c1::Hartnup disease}}: an inherited disorder with intestinal defects ofamino acid absorption and urinary wastage of non-polar andneutral amino acids…
Published	01/20/2024	Symptoms of Hartnup = pellagra - {{c1::Diarrhea, Dementia (also hallucinations), Dermatitis}}
Published	01/20/2024	{{c1::Cystinuria}}: most common inherited diseaseof a.a. transport• results from defective kidney transportsystem for reabsorption of {{c1::cysteine, …
Published	01/20/2024	Cystinuria{{c1::cystine (oxidized cysteine)}} precipitates toform kidney stones (calculi) that can blockurinary tract
Published	01/20/2024	Transamination – amino group transferred to -KG• products are an {{c1::alpha-keto acid}} and {{c1::glutamate}}
Published	01/20/2024	Transamination – amino group transferred to alpha-KGtransfer accomplished by {{c1::aminotransferases.}} All of them require {{c2::pyridoxal phosp…
Published	01/20/2024	all amino acids except {{c1::histidine, threonine and methionine}}participate in transamination in removing alpha-amino groups
Published	01/20/2024	AST primarily transfers amino groups from {{c1::glutamate}} to {{c1::OAA}}, forming {{c2::Asp}}, which is used as a source of nitrogen in the urea cyc…
Published	01/20/2024	{{c1::PLP}} is covalently linked to the ε-amino group of a specific lysine residue at the active site of the enzyme
Published	01/20/2024	AST/ALT << 1.0: {{c1::acute liver damage}} (e.g., viral hepatitis)
Published	01/20/2024	AST/ALT >> 1.0: {{c1::alcoholic hepatitis}}, {{c1::hepatocellular carcinoma}} or {{c1::non-hepatic causes}}
Published	01/20/2024	a05c0bcce79648d7b29c7c2565fe1eb0-ao-1
Published	01/20/2024	a05c0bcce79648d7b29c7c2565fe1eb0-ao-2
Published	01/20/2024	a05c0bcce79648d7b29c7c2565fe1eb0-ao-3
Published	01/20/2024	a05c0bcce79648d7b29c7c2565fe1eb0-ao-4
Published	01/20/2024	Glutamate rapidly deaminated to form alpha-ketoglutarate andammonia; catalyzed by {{c1::glutamate dehydrogenase (GDH)}}:mitochondrial, found in a vari…
Published	01/20/2024	{{c1::Oxidative deamination}}: pathway for amino groups to be released as ammonia (2nd source of nitrogen for urea synthesis in liver)
Published	01/20/2024	GDH is an allosteric enzyme; allostericregulators:- ADP and GDP {{c1::activate}} it; provides alpha-KG for TCA if ATP low.- ATP and GTP {{c1::inh…
Published	01/20/2024	GDH represents a key link between {{c1::catabolic and anabolic}} pathways
Status	Last Update	Fields