Exam - Riboflavin Flashcards
supplement label (B3)
converts carbs, proteins, fats to energy
sources of riboflavin
rich in foods of animal origin
what is riboflavin degraded with
sunlight
examples of bound riboflavin
flavin mononucleotide (FMN)
flavin adenin dinucleotide (FAD)
what must occur to riboflavin that is bound to proteins before absorption
it must be released - done by HCl
where is free riboflavin absorbed
from gut lumen by an active transport mechanism: riboflavin transporter 2 (RFT2)
how does riboflavin, FMN and FAD get transported in body
bound to proteins - particularly albumin
does riboflavin get stored in the body
a little bit in liver, kidney and heart
where does extra riboflavin generally go
generally it gets excreted in urine
how long do sufficient amounts of riboflavin last in body
2-6 weeks
where are FMN and FAD made
in cells
what is the primary form of riboflavin in the body
FAD (60-95%)
what are FMN and FAD involved in
redox reactions
what is FMN and FAD production positively regulated by
T3 hormone - increases activity of the flavokinase enzyme
what element is a part of the enzymes for riboflavin metabolism
Mn or Mg
what is FMN considered
nucleotide
what is FAD considered
a dinucleotide
where does riboflavin function
many biochemical pathways
what is the primary difference between FMN/FAD and NAD(P) in electron transfer
FMN?FAD are bound to the active site of an enzyme
what does FAD do to regenerate glutathione
accepts 2 electrons from NADPH and temporarily becomes FADH2
what does reforming glutathione require
both niacin and riboflavin
when does the signs of riboflavin deficiency appear
after 3-4 months
term for riboflavin deficiency
ariboflavinosis
why is deficiency relatively common when dietary intake is insufficient
because riboflavin is continuously excreted in urine
symptoms of riboflavin deficiency
cracked/red lips
inflammation of mouth lining and tongue
mouth ulcers
cracks at the corners of mouths
populations at risk for deficiency
people with hypothyroidism/thyroid disease
chronic alcoholism
lactose intolerant
is there an upper limit for riboflavin
no
