Remarkable impact of amino acids on ginsenoside transformation from fresh ginseng to red ginseng

Liu, Zhi,Wen, Xin,Wang, Chong-Zhi,Li, Wei,Huang, Wei-Hua,Xia, Juan,Ruan, Chang-Chun,Yuan, Chun-Su The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.3

Background: Amino acids are one of the major constituents in Panax ginseng, including neutral amino acid, acidic amino acid, and basic amino acid. However, whether these amino acids play a role in ginsenoside conversion during the steaming process has not yet been elucidated. Methods: In the present study, to elucidate the role of amino acids in ginsenoside transformation from fresh ginseng to red ginseng, an amino acids impregnation pretreatment was applied during the steaming process at 120℃. Acidic glutamic acid and basic arginine were used for the acid impregnation treatment during the root steaming. The ginsenosides contents, pH, browning intensity, and free amino acids contents in untreated and amino acid-treated P. ginseng samples were determined. Results: After 2 h of steaming, the concentration of less polar ginsenosides in glutamic acid-treated P. ginseng was significantly higher than that in untreated P. ginseng during the steaming process. However, the less polar ginsenosides in arginine-treated P. ginseng increased slightly. Meanwhile, free amino acids contents in fresh P. ginseng, glutamic acid-treated P. ginseng, and arginine-treated P. ginseng significantly decreased during steaming from 0 to 2h. The pH also decreased in P. ginseng samples at high temperatures. The pH decrease in red ginseng was closely related to the decrease in basic amino acids levels during the steaming process. Conclusion: Amino acids can remarkably affect the acidity of P. ginseng sample by altering the pH value. They were the main influential factors for the ginsenoside transformation. These results are useful in elucidating why and how steaming induces the structural change of ginsenoside inP. ginseng and also provides an effective and green approach to regulate the ginsenoside conversion using amino acids during the steaming process.

豆乳의 遊離糖 및 Amino Acids 含量分析

崔震相,崔相道,姜君中,朱玉守,南相海,徐源澤 진주산업대학교 농업기술연구소 1998 農業技術硏究所報 Vol.11 No.-

두유의 유리당 및 amino acids의 함량을 HPLC 및 AAA를 이용하여 분석한 결과는 다음과 같다. 시중 유통 두유에서는 단당류중 fructose와 glucose, 이당류중 sucrose, maltose 및 lactose를 분석하였고, sucrose는 0.78∼9.2 mg/mL의 범위로서 모든 시료에서 측정되었다. 17종의 amino acids를 확인하였으며, 그 조성은 모든 시료에서 비슷하였다. Glutamic acid를 비롯한 산성 amino acids가 전체 amino acids의 40.94%로서 가장 많은 함량이었고, threonine을 포함한 필수 amino acids는 31.78%로 측정되었다. Free sugars and amino acids that contained in soybean milk were analyzed with HPLC and AAA(amino acid analyzer), the results were as follows. Fructose and glucose of monosaccharides, and sucrose, maltose and lactose of disaccharides were detected in soybean milk that collected in market. Sucrose was ranged as 0.78∼9.21 mg/mL and showed in all soybean milk. Amino acids were detected 17 varieties, and the compositions were alike in all soybean milk Contents of acidic amino acids including glutamic acid were 40.94% of total amino acids, and the next order was neutral amino acids as 24.62%. Basic amino acids and aromatic amino acids were 10.83% and 9.20%, respectively. Seven varieties of essential amino acids excluding tryptophan analyzed into 31.78% of total amino acds.

Alterations of Amino Acid Level in Depressed Rat Brain

Yang, Pei,Li, Xuechun,Ni, Jian,Tian, Jingchen,Jing, Fu,Qu, Changhai,Lin, Longfei,Zhang, Hui The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.5

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats' brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats' brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats' brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and ${\gamma}$-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-${\alpha}$-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, ${\gamma}$-amino-n-butyric acid and L-${\alpha}$-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.

구름송편버섯 자실체의 열수와 메탄올 추출물의 아미노산 성분

최병용 ( Byeong Yong Choi ),이형환 ( Hyung H. Lee ) 한국자연치유학회 2017 Journal of Naturopathy Vol.6 No.1-2

구름송편버섯 자실체를 열수(hot water)와 메탄올(methanol)에서 추출하여 추출물의 수율 및 유리 아미노산류와 유기산류의 함량을 조사 분석하였다. 구름송편버섯 자실체 열수 추출물 수율은 0.495 g, 메탄올 추출물은 0.246 g이었으며, 수율은 열수추출이 메탄올 추출보다 약 2배 높았다. 열수추출물에 함유된 유리 아미노산은 총 15종(총 13.59 mg/g)이었고, 이중 leu(2.1 mg/g)이 가장 높았고, arg(1.83 mg/g), ile(1.17 mg/g), tyr(0.03 mg/g) 순이었다. 필수아미노산 함량은 열수 추출물이 메탄올 추출물의 함량보다 약 41배 높았으나, lys은 존재하지 않았다. 메탄올 추출물의 유리 아미노산은 총 6종(총 0.33 mg/g)이었고, 이중 glu이 0.12 mg/g으로 가장 높게 나타났다. 메탄올 추출물에서는 필수아미노산 함량이 총 0.12 mg/g이었다. 유기산 물질의 열수추출은 7종(총 1.26 mg/g)이었고, 이중 γ-aminobutyric acid가 0.63 mg/g, phosphoserine이 0.21 mg/g 이었다. 메탄올 추출물에서의 유기물은 phosphoserine과 β-amino-isobutyric acid의 2종이 확인되었으며, 총 0.09 mg/g이었다. 이중 β-amino-isobutyric acid는 열수 추출물에는 존재하지 않았으나, 메탄올 추출물에서는 확인이 되었다. 구름송편버섯 자실체 열수와 메탄올 추출물에는 여러 종류의 아미노산과 유기산이 추출되어서 단백질의 아미노산 기능과 유기산 등의 기능이 다양한 영양학적 또는 기능성 원료로서의 활용 가능성이 있는 것으로 사료된다. This study was to analyze, using HPLC method, the quantity and types of L-amino acids and organic compounds found in Coriolus versicolor fruitbody extracts in hot water and methanol. The total quantity of the C. versicolor extracts was 0.495 g in the hot water, the methanol extract appeared to 0.246 g, the water extracts showed about two times higher than the content of methanol extract. Fifteen types of L-amino acids and seven kinds of organic acids were found in the both extracts. The total quantity of the free amino acids were 13.59 mg/g in the hot water extracts, and the amounts of leu was highest with 2.1 mg/g, and the rest ranged from arg(1.83 mg/g), ile(1.17 mg/g) and tyr(0.03 mg/g). The total quantity of the free amino acids were 0.33 mg/g and six types of amino acids in methanol extracts, and the amounts of glu was highest with 0.12 mg/g, and the rest ranged from arg(1.83 mg/g), ile(1.17 mg/g) and tyr(0.03 mg/g). Amounts of essential amino acids were 41 times more presented in the hot extracts than the methanol extracts, however lys was not in the hot extract. The hot extracts contained seven types of organic acids and total quantity was 1.26 mg/g; ?-aminobutyric acid was 0.63 mg/g, phosphoserine was 0.21 mg/g. The methanol extract contained phosphoserine and β-amino-isobutyric acid and total amounts was 0.09 mg/g. β-amino-isobutyric acid was in the hot water. The finding supports that C. versicolor fruitbody extracts from hot water and methanol are useful to basic information in nutritional and functional materials.

Alterations of Amino Acid Level in Depressed Rat Brain

Pei Yang,Xuechun Li,Jian Ni,Jingchen Tian,Fu Jing,Changhai Qu,Longfei Lin,Hui Zhang 대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.5

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology ofdepression. Several studies have demonstrated the potential of amino acids as a source of neuro-specificbiomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycineand asparagine were determined from certain parts of rats’ brain included hippocampi and cerebralcortex in previous studies. However, according to systematic biology, amino acids in different areaof brain are interacted and interrelated. Hence, the determination of 34 amino acids through entirerats’ brain was conducted in this study in order to demonstrate more possibilities for biomarkers ofdepression by discovering other potential amino acids in more areas of rats’ brain. As a result, 4 aminoacids (L-aspartic acid, L-glutamine, taurine and γ -amino-n-butyric acid) among 34 were typicallyidentified as potentially primary biomarkers of depression by data statistics. Meanwhile, anantidepressant called Fluoxetine was employed to verify other potential amino acids which were notidentified by data statistics. Eventually, we found L-α -amino-adipic acid could also become a newpotentially secondary biomarker of depression after drug validation. In conclusion, we suggested thatL-aspartic acid, L-glutamine, taurine, γ-amino-n-butyric acid and L-α-amino-adipic acid might becomepotential biomarkers for future diagnosis of depression and development of antidepressant.

Expression and Functional Characterization of Neutral Amino Acid Transporter in HEp2 Human Head and Neck Squamous Cell Carcinoma

Kim, Do Kyung,Yoon, Jung Hoon,Jeon, Jeong Hoon,Lee, Sang Ho Korean Academy of Oral Biology and the UCLA Dental 2004 International Journal of Oral Biology Vol.29 No.2

Amino acid transporters are essential for growth and proliferation in normal and transformed cells. Among the amino acid transport systems, the system L amino acid transporter is a major nutrient transport system responsible for the Na^(+)-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1 (LAT1) is up-regulated to support tumor cell growth. In this study, we have investigated the expression and functional characterization of system L amino acid transporter in HEp2 human laryngeal squamous cell carcinoma. RT-PCR, real-time quantitative RT-PCR and western blot analysis have revealed that the HEp2 cells express LAT1 together with its associating protein, heavy chain of 4F2 antigen (4F2hc), whereas the HEp2 cells do not express the L-type amino acid transporter 2 (LAT2), the second isoform of system L amino acid transporter. The uptake of [^(14)C]L-leucine by HEp2 cells is Na^(+)-independent and almost completely inhibited by system L amino acid transporter selective inhibitor 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). The inhibition profile of [^(14)C]L-leucine uptake by various amino acids in the HEp2 cells is comparable with those for the LAT1 expressed in Xenopus oocytes. The majority of [^(14)C]L-leucine uptake is, therefore, mediated by LAT1 in the HEp2 cells. These results suggest that the transport of neutral amino acids including several essential amino acids in the HEp2 human laryngeal squamous cell carcinoma mediated by LAT1. In addition, the specific inhibition of LAT1 in head and neck squamous cell carcinomas will be a new rationale for anti-cancer therapy.

Reabsorption of Neutral Amino Acids Mediated by Amino Acid Transporter LAT2 and TAT1 in The Basolateral Membrane of Proximal Tubule

Park Sun Young,Kim Jong-Keun,Kim In Jin,Choi Bong Kyu,Jung Kyu Yong,Lee Seoul,Park Kyung Jin,Chairoungdua Arthit,Kanai Yoshikatsu,Endou Hitoshi,Kim Do Kyung The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.4

In order to understand the renal reabsorption mechanism of neutral amino acids via amino acid transporters, we have isolated human L-type amino acid transporter 2 (hLAT2) and human T-type amino acid transporter 1 (hTAT1) in human, then, we have examined and compared the gene structures, the functional characterizations and the localization in human kidney. Northern blot analysis showed that hLAT2 mRNA was expressed at high levels in the heart, brain, placenta, kidney, spleen, prostate, testis, ovary, lymph node and the fetal liver. The hTAT1 mRNA was detected at high levels in the heart, placenta, liver, skeletal muscle, kidney, pancreas, spleen, thymus and prostate. Immunohistochemical analysis on the human kidney revealed that the hLAT2 and hTAT1 proteins coexist in the basolateral membrane of the renal proximal tubules. The hLAT2 transports all neutral amino acids and hTAT1 transports aromatic amino acids. The basolateral location of the hLAT2 and hTAT1 proteins in the renal proximal tubule as well as the amino acid transport activity of hLAT2 and hTAT1 suggests that these transporters contribute to the renal reabsorption of neutral and aromatic amino acids in the basolateral domain of epithelial proximal tubule cells, respectively. Therefore, LAT2 and TAT1 play essential roles in the reabsorption of neutral amino acids from the epithelial cells to the blood stream in the kidney. Because LAT2 and TAT1 are essential to the efficient absorption of neutral amino acids from the kidney, their defects might be involved in the pathogenesis of disorders caused by a disruption in amino acid absorption such as blue diaper syndrome.

야생 돌복숭아 씨와 과육의 아미노산 및 지방산 조성에 관한 연구

김한수,Kim, Han-Soo 한국생명과학회 2007 생명과학회지 Vol.17 No.1

우리나라 전역에서 자생하는 야생 돌복숭아(Prunus persica Batsch var, davidiana Max.)의 씨와 과육 중의 각종 생리활성 물질을 규명하여 바이오헬스 기능성 소재 등의 자원으로서 이용 가능성을 검토하기 위한 자료로, 돌복숭아 씨와 과육 중의 일반성분, 구성 총 아미노산, 유리 아미노산 및 지질 구성 지방산 조성을 분석한 결과는 다음과 같다. 돌복숭아 씨 및 과육 중의 일반성분 함량은 탄수화물이 63.92% 와 75.11%로 대부분을 차지하였으며, 조단백질 27.85%, 12.77%, 수분 3.61%, 4.69%, 조지 방이 1.21%, 4.80% 그리고 조회분이 3.41%와 2.63% 함유되어 있는 것으로 나타났다. 돌복숭아 씨 중의 구성 총 아미노산의 함량은 3,444.35 mg%로 이 중 aspartic acid가 681.10 mg%, glutamic acid 495.48 mg%, alanine 283.66 mg%, serine 251.36 mg%, proline 229.80 mg%, lysine 192.31 mg% 및 leucine이 191.34 mg%의 순으로 조성되어 있었으며, 특히 aspartic acid 및 glutamic acid가 대부분을 차지하였다. 돌복숭아 과육의 단백질 구성 아미노산 조성의 총 함량은 1,064.02 mg%로, aspartic acid 250.15 mg%, glutamic acid는 129.63 mg%로 과육의 주요 총 아미노산이었고 lysine, proline, leucine, alanine, serine 등의 순으로 함유되어 있었다. 돌복숭아 씨 중 유리 아미노산 조성의 총 함량은 6,215.34 mg%로, 이 중 glutamic acid가 827.25 mg%로 가장 많았으며, threonine, valine, $\beta-aminobutyric$ acid 등의 순으로 함유되어 있었다. 과육 중의 유리 아미노산 조성의 총 함량은 683.82 mg%로, glutamic acid(339.49 mg%)가 대부분 이었으며, serine, proline, alanine, $\gamma-amino-n-butyric$ acid의 순으로 함유되어 있었다. 지질 구성 지방산 조성은 포화지방산이 12.49%, 단불포화지방산 13.11% 및 다불포화지방산이 74.36%의 함유비율을 보였으며, 필수지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다. Amino acid and fatty acid compositions of the physiological activity substance in the seed and pulpy substance of feral peach (Prunus persica Batsch var. davidiana Max.) were analyzed for the use as an biohealth functional processed products. The proximate compositions in the vacuum freeze dried seed and pulpy substance of feral peach were carbohydrate 63.92% and 75.11%, crude protein 27.85% and 12.77%, moisture 3.61% and 4.69%, crude fat 1.21% and 4.80%, crude ash 3.41% and 2.63%, respectively. Total amino acid contents in the protein of feral peach seed were 3,444.35 mg%, and the major amino acids were aspartic acid(681.10 mg%), glutamic acid(495.48 mg%), alanine(283.66 mg%), serine(251.36 mg%), proline(229.80 mg%), lysine(192.31 mg%) and leucine(191.34 mg%), respectively. Total amino acid contents in the protein of feral peach pulpy substance were 1,064.02 mg%, and the major amino acids followed aspartic acid(250.15 mg%), glutamic acid(129. 63 mg%), lysine, proline, leucine, alanine and serine, in a decreasing order. The richest total amino acid content contained in feral peach seed and pulpy substance was aspartic acid, followed by glutamic acid. The amount of free amino acids of feral peach seed were 6,215.34 ms%, and the major free amino acids were glutamic acid(827.25 mg%), threonine, valine and $\beta-aminobutyric$ acid, respectively. Free amino acid contents of pulpy substance were 683.82 mg%, and the major free amino acids were glutamic acid(339.49 mg%), serine proline, alanine and $\gamma-amino-n-butyric$ acid. Especially, in the case of glutamic acid, it was highest. The compositions of major total fatty acid in the lipid feral peach (Prunus persica Batsch var. davidiana Max.) seed and pulpy sabstance were linoleic acid($C_{18:2}$, n-6) and linolenic acid($C_{18:3}$, n-3), particularly.

스포츠생리학 : 철인 3종 경기 전·후 혈장 및 뇨 아미노산 농도의 변화와 피로의 관련성

나재철(JaeChulNa),김정태(JumgTaeKim) 한국체육학회 1999 한국체육학회지 Vol.38 No.3

본 연구는 기존의 선수경력과 경기기록에 근거하여 트라이애슬론 선수권 대회에 엘리트 그룹과 일반선수그룹으로 참가한 남자트라이애슬론 선수들을 대상으로 경기전·후 혈장 및 뇨 아미노산 농도의 변화를 비교·검토하였다. 또한, 실전 트라이애슬론 경기후 혈장 아미노산 농도의 변화에 근거한 중추성피로의 발생가능성을 살펴본 결과 다음과 같은 결론을 얻었다.경기전 공복시 총혈장과 뇨 아미노산 농도를 비교한 결과 엘리트군이 일반선수군보다 유의하게(p<.01) 낮은 것으로 나타났다. 경기후 엘리트군에서 혈장 아미노산농도는 이소루신(-26%), 리신(-1%), 세린(-1%), α-아미노부티릭산(-27%), 1-메틸히스티딘(-33%), 아르기닌(-1%)을 제외한 나머지 22개의 개별아미노산은 증가를 나타낸 반면, 일반선수군에서 혈장 아미노산 농도는 메티오닌(+25%), 트립토판+53%), 아스파르트산(+20%), 시스틴(+12%), 티로신(+5%), 에타놀아민(+23%) 및 3-메틸히스티딘(+58%)을 제외한 나머지 21개의 개별아미노산은 감소를 나타내었다. 경기 후 엘리트군에서 뇨아미노산의 농도는 필수아미노산(+17%), 비필수아미노산(+9%) 및 총 뇨아미노산(+10%)에서 증가를 나타낸 반면, 일반선수군에서 뇨아미노산의 농도는 필수아미노산(-15%), 비필수아미노산(-19%) 및 총 뇨아미노산(-19%)에서 유의한(p<0.05) 감소를 나타내었다. 그리고 경기 후 황함유 아미노산(타우린, 시스틴, 메티오닌) 및 방향족 아미노산(페닐알라닌, 티로신, 트립토판)의 증가, 분기쇄 아미노산(루신, 이소루신, 발린)의 감소 및 AAA/BCAA의 비율과 Trp/BCAA비율이 경기전보다 증가한 것은 중추성 피로의 발생 가능성이 높은 것으로 간주된다. 이상의 결과에서 을림픽코스 트라이애슬론 경기는 엘리트군과 일반선수군에서 혈장과 뇨 아미노산 농도의 불균형을 초래한 것으로 간주된다. 특히, 경기수행시간이 더 길었던 일반선수군이 엘리트군 보다 혈장아미노산 농도가 훨씬 더 감소한 것으로 나타나므로써 경기수행 능력에 부정적인 영향을 미칠 수 있음을 시사하였다. This study investigated the relationship of central fatigue and changes in plasma and urine concentrations of amino acid before and after an olympic course triathlon. The subjects of this experiment were 14 well-trained men participated in a `97 Sokcho triathlon event, on a cool, cloudy and windy day. Of all the subjects, 7 triathletes consisted of the elite group(EG) and 7 triathletes were composed of the age group(AG), respectively. Prior to the start of triathlon, 5㎖ blood was taken from the antecubial vein and 20㎖ urine of the subjects were taken, respectively. Blood and urine were again taken from the subjects at the end of triathlon event. Plasma and urine amino acids were determined by Biochrome 20 Amino Acid Analyzer. Blood urine nitrogen and uric acid were determined by Hitachi 7150. FFA was measured by spectrophotometer. Before triathlon event, total plasma and urine amino acid concentrations showed significantly(p<.05) decrease in EG than that of AG. As compared to pre-race, Plasma amino acid concentrations of post-race in EG were increased in 22 individual amino acids by 1∼112%, and decreased in isoleucine(-26%), lysine(-1%), serine(-1%), α-aminobutyric acid(-27%), 1-Methylhistidine(-33%), and arginine(-1%). In contrast to the above, Plasma amino acid concentrations of post-race in AG were decreased in 21 individual amino acids by 1∼47%, and increased in methionine(+25%), tryptophan(+53%), aspartate(+20%), cystine(+12%), tyrosine(+5%), ethanolamine(+23%), and 3-Methylhistidine(+58%). As compared to pre-race, Urine amino acid concentrations of post-race in EG were increased in EAA(+17%), NEAA(+9%), and TAA(+10%), while significantly(p<0.05) decreased in EAA(-15%), NEAA(-19%), and TAA(-19%) in AG. As compared to pre-race, Sulfur-containing amino acids(taurine, cystine, methionine), aromatic amino acids(phenylalanine, tryptophan, tyrosine), AAA/BCAA, and Trp/BCAA ratio of post-race were increased. It could be regarded that there was the relationship between the central fatigue and plasma concentrations of amino acid. These results were considered as causing olympic course triathlon event to result in imbalance of plasma and urine amino acid concentrations in two groups. During triathlon event, changes in individual amino acid concentrations were found to have a significant difference from precompetition stress, intensity of exercise and duration of exercise as well as metabolic process state by subject`s physiological condition and environmental condition, before and during the event diet condition.

Nutritional Quality and Variation of Meat and Bone Meal

Hendriks, W.H.,Butts, C.A.,Thomas, D.V.,James, K.A.C.,Morel, P.C.A.,Verstegen, M.W.A. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.10

Meat and bone meal is a valuable protein and mineral source in diets of production animals and contributes to the protein, energy and mineral component of diets. The aim of the present study was to more accurately characterise the apparent ileal amino acid digestibility of meat and bone meals produced in New Zealand and evaluate routine in vitro assays used in practise to measure meat and bone meal quality. A total of 94 commercial meat and bone meals from 25 New Zealand rendering plants over a two and a half year period were analysed for proximates, gross energy, gross amino acid content (incl. hydroxyproline, hydroxylysine and lanthionine), apparent ileal amino acid digestibility, pepsin nitrogen digestibility, protein solubility and bone content. The mean crude protein content of the 94 meat and bone meal samples was 56.8% with a range of >35% units and a coefficient of variation of 9.8%. The mean crude fat and ash content were 10.0 and 28.4% respectively. These latter components showed a large range (16 and 43%, respectively) with coefficients of variation above 22%. Amino acid digestibility between samples was highly variable with lysine and sulphur amino acids digestibility ranging between 45.8-89.0 and 38.2-85.5%, respectively. Pearson correlation coefficients are presented between crude protein content and individual gross amino acids, crude protein content and individual digestible amino acid content, and pepsin N digestibility and individual digestible amino acid content. There was a significant relationship between the digestible amino acid nitrogen content and the crude protein content while pepsin nitrogen digestibility was not correlated to ileal amino acid nitrogen digestibility (r=-0.06). Meat meals with a high protein content had relatively low hydroxyproline and hydroxylysine levels something that was attributed to the levels of collagen from bone. The data indicated that lanthionine (formed upon heat treatment of cysteine with a hydroprotein) is not a good indicator of the heat treatment employed to meat and bone meals. Step-wise multiple regression equations to predict the apparent digestible content of amino acids from rapid in vitro assays are presented. The most selected variables included ash and crude fat content. In general the equations derived for the essential amino acids had a higher degrees of fit (R2) compared to the non-essential amino acids. The R2 for the essential amino acids ranged from 0.43 for histidine and 0.68 for leucine. These equations provide a means of more rapidly estimating the apparent ileal digestible amino acid content (protein quality) of meat and bone meal using standard analyses.