Miraculin (1-20) is a peptide, comprised of 20 amino acids[1].
References
[1] Brouwer JN, et al. The sweetness-inducing effect of miraculin; behavioural and neurophysiological experiments in the rhesus monkey Macaca mulatta. J Physiol. 1983 Apr;337:221-40. DOI:10.1113/jphysiol.1983.sp014621