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Exam 1 Terms (lec 1-5)
Terms in this set (71)
Polypeptide composed of 20 AA covalently linked via peptide bonds
Provide proteins the ability to carry out specific functions via their distinctive side chains
folded protein conformation which resembles a ball or globe
ex: Serum albumin
Folded protein which resembles a fiber
Enzyme which cleaves protein substrates into different parts
enzyme which adds phosphate to serine, threonine, or tyrosine side chains on proteins.
Phoshpate donated by atp
enzyme which cleaves phosphate off of proteins
RNA w/ catalytic fxn similar to protein enzymes
Having a multi-ring organic structure which imparts the characteristic of water insolubility on these materials
*All steroid hormones are synthesized from cholesterol
*water soluble protein hormones
ex: insulin, glucagon, PTH
Class of intracellular proteins responsible for recognizing and binding to steroid hormones and thyroxine
*IMPORTANT for regulating gene expression
Cell surface receptor
For hormones that are hydrophilic so can't pass thru cell membrane
Hormone response element
duplicated short 6-10 bp DNA sequence in promoter region of hormone response gene.
It binds the nuclear receptor and hormone complex
relay signals from receptors
3 types of second messengers
1. Hydrophilic (cAMP, cGMP)
2. Hydrophobic (diacylglycerol
3. Gases (nitric oxide)
Cells responding to signals released at a distance and traveling via the bloodstream
responding to signals within local environment
responding to signals within a similar, close cell
ex: immune cells
requires physical contact between two cells
a disease in which the body does not properly control the amount of sugar (glucose) in the blood.
-is not precisely defined and the lack of a consensus on diagnostic criteria has made its genetic analysis difficult.
- 9% of the adult US population has diabetes.
2 Major forms of Diabetes Mellitus
Type 1: insulin-dependent diabetes mellitus (IDDM)
Type 2: noninsulin-dependent diabetes mellitus (NIDDM) (85-90% of all diabetic cases)
common and mild form of gum disease causing irritation, redness, and swelling (inflammation)
-Can evolve into periodontitis
serious gum infection that destroys the soft tissues and bone that support the teeth
-Diabetic Retinopathy (blindness)
-Diabetic Nephropathy (renal disease)
-Diabetic Neuropathy (lower extremity amputations)
The insulin receptor is a
tyrosine kinase receptor
Advanced glycation end products
Results from covalent modification of proteins in vascular tissue and blood, as a result of high levels of blood glucose
-causes upscure problems which end up affecting kidney, wound healing, and eye
-Biomarker in blood which provides a measure of how well diabetes is managed.
-its a varient of hemoglobin
-it circulates in blood for long time (120 days)
Angiotensin & renin
Peptide hormone that causes VASOCONSTRICTION aka rise in blood pressure.
Nitric Oxide (NO)
Powerful VASODILATOR w/ short half life of few seconds in blood
injectable form of glucagon is important for severe hypoglycemia
Receptor of advanced glycation endproducts
-mediates intracellular signaling upon binding of its ligand
Proteolytic enzyme which cleaves angiotensinogen to yield angiotensin 1
Symptoms of Hyperglycemia
(higher than 200 mg/dl vs normal person with 100 mg/dl)
How does insulin stimulate lipogensis?
Acts on 2 targets
Did you know that Type I diabetes...
-Disease of human immune system
-destroys beta cells in pancreas
Symptoms of hypoglycemia
-blood sugar below 70 mg/dl
ACE inhibitors stop...
Tiny hemorages that exist in blood vessels of eye
-can obscure vision
fatty acid release
enzyme which cleaves protein substrates into different parts. Trypsin prefers to cleave at arginine and lysine residues; it is a "serine" protease which serine at the "active site".
enzyme which adds phosphate to serine, threonine, or tyrosine side chains on proteins. Phosphate is usually donated by ATP.
enzyme which cleaves phosphate off of proteins.
protein which possesses catalytic activity, e.g., ability to catalyze a chemical reaction. Not all enzymes are proteins.
RNA with catalytic function similar to protein enzymes.
non-catalytic protein which provides essential structural support for tissues and organs, e.g., collagens, elastin, proteoglycans, etc.
polypeptide hormone produced by beta-cells of the pancreas which stimulates uptake of glucose by cells ("fed state")
polypeptide hormone produced by alpha-cells of the pancreas which raises blood glucose level in blood (opposite of insulin).
transmembrane proteins which facilitate the transport of glucose through the plasma membrane of cells, e.g., Glut4 or SLC2A
Insulin receptor :
tyrosine kinase transmembrane receptor that is activated by insulin, IGF-I, IGF-II and belongs to the large class of tyrosine kinase receptors.
Phosphorylation occurs on specific side chains of enzymes or receptors:
serine, threonine, tyrosine, and histidine.
- Incretins are gastrointestinal hormones which increase pancreatic insulin secretion by binding to and activation of GLP-1 receptor on pancreatic cells.
-incretin effect is increased with oral glucose (not direct glucose intravenously)
-The effects of incretin hormones are believed to be responsible for up to 60% of postprandial insulin release.
Dipeptidyl peptidase-4 (DPP-4)
-DPP-4 rapidly degrades GIP and GLP-1.
- Now there are drugs to stop this,
DPP-4 inhibitors, which block degradation of GLP-1, and GLP-1 receptor agonists, which block uptake of GLP-1 by cells and which are themselves resistant to degradation by DPP-4.
blocks binding of hormone to its receptor while binding and activating the receptor itself
inhibitory blocker of hormone or agonist binding to its receptor
protein receptor with hormone with three binding sites---hormone binding site, trans-activator domain and DNA binding domain
Non-genomic actions of steroid hormones:
genome independent actions of steroid hormone on ion channel, transporter, etc.
Genomic actions of steroid hormones:
to change gene expression via binding to promoter regions of specific responsive genes
-estrogen responsive element:
specific short DNA sequence representing nuclear binding site for estrogen receptor protein and hormone complex
SERMS: Selective estrogen receptor modulators,
-Can act as agonist or antagonist depending on tissue (inhibit or stimulate estrogen-like action)
-Example: raloxifene which is an estrogen agonist in bone but an antagonist in breast and uterus.
(glucose + cortex + steroid)
Fxn: regulates metabolism of glucose
Synthezised by: adrenal cortex
Binds: glucocorticoid receptor (nuclear receptor)
- Have potent immunosuppressive effects in vivo to block inflammation.
Steroid binding protein:
protein binder of specific hormone; together the two (binding protein and steroid) circulate as a complex to overcome the insolubility of the steroid hormones in aqueous media like blood plasma.
Androgen insensitivity syndrome:
mutations in the hormone binding region cause absence of hormone binding or qualitative/quantitative changes leading to testicular feminization or Reifenstein syndrome
Generalized glucocorticoid resistance:
mutation in ligand binding domain of GR-alpha. Presented with history of fatigue, anxiety, hyperandrogenism, and hypertension
Congenital hypothyroidism nongoitrous:
mutation in THRA gene which produces dominant negative form capable of antagonizing normal receptor function in nucleus—reduced expression of thyroid hormone responsive genes.
Graves disease (autoimmune hyperthyroidism):
auto-antibody which binds to thyroid stimulating hormone receptor on thyroid gland causing secretion of more thyroxine.
-naturally occurring substance capable of stimulating cellular growth, proliferation, and differentiation.
-Growth factors signal by generally binding to a specific cell surface receptor on the surface of susceptible cells.
-Growth factors play a critical role in embryonic growth, cell survival, and in wound healing in adults.
A pro-hormone which requires metabolic activation to generate the most active chemical form.
-Cathelicidins serve a critical role in mammalian innate immune defense against invasive bacterial infection; broad spectrum antibacterial activity.
-antimicrobial peptides found in lysosomes of macrophages and polymorphonuclear leukocytes (PMNs).
-family of small cysteine rich cationic peptides.
-Alpha defensins are highly expressed in neutrophils, beta defensins are secreted by mucosal epithelia. Both are found in saliva and crevicular fluid where they prevent early colonization by pathogens.
-Leukocytes of the immune system contain these peptides to assist in killing phagocytosed bacteria, for example in neutrophil granulocytes and almost all epithelial cells.
a softening of bones in immature mammals due to deficiency or impaired metabolism of vitamin D, phosphorus or calcium, potentially leading to fractures and deformity
Vitamin D nuclear receptor (VDR)
-a transcription factor regulating the expression of genes which mediate its biological activity (member of large family of nuclear hormone receptors
-Upon binding 1,25-(OH)2-Vitamin D3, VDR forms a heterodimeric complex with other nuclear hormone receptors, particularly the Retinoid-x-receptor.
-Heterodimeric complex binds to DNA promoter sequences containing VDRE or vitamin D response element sequences in genes it regulates.
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