Ex. 18 Lysine Decarboxylase

Question 1

decarboxylation

Answer 1

removal of carboxyl group (-COOH) yielding CO2 and amine (RCH2NH2) if decarboxylating aa

Question 2

lysine decarboxylase releases

Answer 2

CO2 and amine cadaverine

Question 3

pyridoxyl phosphate

Answer 3

coenzyme that enhances decarboxylase activity

Question 4

Lysine Decarboxylase Broth components

Answer 4

aa lysine, fermentable carbohydrate (dextrose), pH indicator dye and Durham tube (inverted vial)

Question 5

optimal condtions for decarboxylation

Answer 5

anaerobic and acidic

Question 6

how are anaerobic conditions maintain

Answer 6

layering sterile mineral oil over surface of broth. prevents 02 from reaching bacteria and inhibiting reaction

Question 7

how are acidic condtions reached

Answer 7

bacteria themselves. initially will ferment sugar in tube. fermentation of glucose yields acid

Question 8

how are amine molecules accummulated

Answer 8

once acidic, bacteria decarboxylate lysine producing cadaverine

Question 9

when will pH indicator be basic

Answer 9

cadaverine accumulates pH is higher. also C02 release

Question 10

what is +ive test for lysine decarboxylase

Answer 10

basic conditions and presence of gas

Question 11

what other aa can be substituted to test for other aa decarboxylase

Answer 11

arginine and ornithine