1.04 UTF-8 0 0 0 what is going on with cystinuria 2 a genetic defect in an amino acid trasport system involved in the trasport of basic amino acids and cysteine in the intestine and kidney. Because cysteine can't be transported efficiently in the kidney, it accumulates in the urine where it rapidly oxidizes to cystine which precipitates because of its low solubility. 1 what is hartnup disease 2 genetic defect in neutral amino acid transport--deficiency of tryptophan-->nicotinic acid--> niacin resembles pellagra 1 what are considered to be important counterions for polyanions 2 polyamines polyamines stimulate a number of reactions of the nucleic acids 1 what are some causes of carnitine deficiencies 2 genetic defects in carnitine sythesis kidney dysfunction hemodialysis patients premature infants 1 carnitine is synthesized from ___________ residues. 2 trimethyllysine 1 what are three functions of reduced glutathione 2 reduce disulfide bonds in proteins reduce highly reactive peroxides conjugated to hydrophobic molecules to be excreted in the urine 1 what are three main types of symptoms caused by porphyrias 2 neuropsychiatric symptoms phtosensitivity abdominal pain 1 what is the function of carotenoids 2 singlet-oxygen scavenger 1 what is produced immediately after the photosensitivity reaction of people with porphyrias 2 single oxygen 1 what can be given to patients with porphyrias to repress the biosynthetic enzymes 2 hematin 1 what gives stool its color 2 degraded bilirubin --> urobilins 1 what are three pathways by which nucleotides are sythesized? 2 de novo salvage catabolic 1 IMP serves as a precursor for both __________ and ___________ 2 AMP GMP 1 where does PRPP come from 2 ribose-5-phosphate from the PPP 1 the salvage of bases requires the activity of ____ which utilize PRPP as the ribose phosphate donor. 2 phosphoribosyltransferases 1 what are two phophoribosyltransferases 2 HGPRTase (hyposanthine-guanin phosphoribosyltransferase) APRTase (adenin phosphoribosyltrasferase) 1 what is the result of excessive levels of uric acid/urate in the body and how does this happen 2 gout due to excessive degradation of purines 1 how does one treat gout? 2 allopurinol which inhibits xanthine dehydrogenase/xanthine oxidase activity, thus inhibiting the generation of uric acid 1 gout is mutually exclusive with what other disease? 2 MS 1 what is 6-mercaptopurine used for and how does it work? 2 anticancer drug inhibits do novo pathway and IMP dehydrogenase --> no purine or guanine --> cancer no likey 1 what is methotrexate used for and how does it work 2 cancer chemotherapeutic agent, early abortion inhibitor of dihydrofolate reductase-->deficiency in several folates which are required for de novo pathway--> no purine nucleotide 1 what causes severe combined immunodificiency disease (SCID) 2 adenosine deamniase deficiency this is bubble baby stuff 1 what is the genetic disease when people are completely devoid of the salvage enzyme GHPRT 2 Lesch-Nyhan syndrome self mutilation 1 how are deoxynucleotides synthesized 2 de novo through enzyme ribonucleotide reductase which uses NADPH as a reductant 1 in what form must both ribonucleotides and deoxyribonucleotides be converted to function as precursors of RNA or DNA synthesis 2 triphosphate 1 what is acyclovir used for and how does it work? 2 antiviral agent--herpes it is phosphorylated. This form is used in the DNA of viruses, but not mammals and thus terminates growing DNA chains of viral DNA 1 PRPP is used in the first step to the eventual formation of what important compounds 2 IMP-->AMP and GMP 1 Tryptophan is a precursor of the neurotransmitter _____________ and the hormone _____________ 2 serotonin melatonin 1 where does GABA come from 2 decarboxylation of glutamate 1 where does histamine come from? 2 decarboxylation of histidine 1 Tryptophan and serotonin are important in the formation of what product that is important in circadiane rhythms? 2 melatonin 1 what AA is the precursor for NO and citrulline 2 arginine 1 from which two amino acids is creatine synthesized from 2 arginine and glycine 1 what is made from trimethyllysine residues? 2 carnitine 1 glutathione is a tripeptide sulfhydryl that involves what three AAs 2 glycine, cysteine, and glutamate 1 what is the enzyme that is involved in the conjugation role of reduced glutathione 2 glutathione-S-transferase 1 the biosynthesis of poryphyrins starts with ______________ and __________________ and leads to the synthesis of porphobilinogen 2 glycine succinyl-CoA 1 porphyrins are more highly oxidized and are ____________, the porphyrionogens are not 2 colored 1 what is ALA a precurser of? 2 heme 1 what are some common triggers for porphyria attacks 2 barbiturates griseofulvin anesthetics alcohol anything that triggers cytochrom P450's (foods rich in carbohydrates) 1 what is the benefit to measuring the levels of bilirubin in the serum? 2 hemolytic anemias various forms of hepatitis bile duct obstruction 1 uric acid is a antioxidant eqhich is reported to scavenge ____________ 2 peroxynitrite 1