TI9- antibiotic chemistry 2

list the different types of beta lactam antibiotics

describe beta lactam antibiotics and their functions 

they are very reactive to electron rich molecules e.g particular residues within enzymes

describe the beta- lactam antibiotic  reaction 

• the antibiotic e.g. penicilin binds to a bacterial enzyme e.g. penicillin- binding protein which would normally hlep the bacteria form their cross linkages in their cell wall 

• the beta lactam ring opens- the enzyme attacks the beta lactam ring in penicillin opening it and forming a stong covalent bond with the antibiotic 

• the enzyme becomes inactive- the antibiotic remains attached to the enzyme preventing it from carrying out normal functions, the bacteria can no longer cross link their cell wall 

• the bacterial cell bursts- without the maintained cell wall, the growing bacterium becomes vulnerable to internal pressure and bacterial lysis occurs 

describe how resistance in beta lactams and other antibiotics occur 

• target modification- this is when the penicilin binding protein is changed so that the antibiotic becomes less effective

• amidases- they remove the penicillin side chain which makes the antibiotic bind less well to the penicillin binding protein so resistance occurs.

• beta-lactamases 

what are beta- lactamases and how do they cause resistance 

• they are enymes that are prodcued by the bacteria that destroy the beta lactam on antibiotics making them inneffective 

• the antibiotic reaches the bacteria- normally it would bing onto the penicilin binding protiens stopping the bacteria from building a strong cell wall 

• the bacteria produce a beta lactamases- this enzyme attacks the open beta lactam ring with is essentizl for its activity 

• the antibiotic is inactivated- the enzyme forms a brief aceyl- enzyme intermediate which is then rapidly broken down into penicilloic acid which causes the enzyme to attack more antibiotic molecules 

• the bacteria survive.

what are the different type of beta lactamases 

what are some ways of overcoming beta lactamases + problems with it 

• develop new antibiotics which are resistant to hydrolysis of beta lactamses 

is is done a lot but resistance is able to quickly develop to new antibiotics espically in hosptials where theres intensive use. 

also theres a limited number of antibiotics that need to be discovered as most have already been discovered 

also patients often fail to take their full course of antibiotics which increases the problem of resistance 

how are new antibiotics discovered 

what are semi-sythetic penicllins 

these are peniclins with different side which are developed by modifying/manipulating the biosythetic pathway for penicllin 

describe penicilin biosythesis 

explain how penicilins’s are engineered